Haynes Techbook Diesel Engine Repair Manual [10330] 156392188X, 9781563921889

Citation preview

10330(1736)

f

i

Engine Repair

IVlanual

«

"

General Motors and Ford

'~ ^

Light Trucks, Vans, Passenger Cars

General Motors 350 cu in (5.7 liter) 379 cu in (6.2 liter) • 397 cu in (6.5 liter) Ford 420 cu in (6.9 liter) • 445 cu in (7.3 liter) 445 cu in (7.3 liter Power Stroke)

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Step-by-Step Instructions F""y Illustrated for the Home Mechanic Simple Maintenance to Major Repairs

(^

i % ^ I'CLEO?^

^yne

TECiBOaK

Boston Public Library

Diesel

Engine Repair

Manual by Ken Freund and John H Haynes Member

of the Guild of

Motoring Writers

General Motors and Ford V8 diesel engines:

GM

350 cu

In (5.7L),

Ford 420 cu

In

(6.9L)

397 cu

in

(6.5L)

and 445 cu

In

and 379 cu

(7.3L)

(11Z10- 10330) (1736)

AinoMonvii h

ftvirre

')^^^ Haynes Publishing Group Sparkford Nr Yeovil Somerset BA22 7JJ England

Haynes North America, 861 Lawrence Drive Newbury Park California

91320

USA

Inc.

A _ MEMBER

In

(6.2L)

BR BR

TL230.5 .657

F74^

1997 k

Acknowledgements

We are grateful to the General

Motors Corporation and the Ford assistance with technical infornnation and certain illustrations. The Federal-Mogul Corporation supplied the illustrations of various engine bearing wear conditions. Technical writers who contributed to this project include Mike Stubblefield, Robert Maddox and Larry Warren. Portions of materials conMotor Company

for

tained herein have been reprinted with pemriission of General Motors Corporation, Service Technology Group.

©

Haynes Publications,

Inc.

With permission from J.H. Haynes

& Co.

A book

in

the

1991, 1994, 1997 Ltd.

Haynes Automotive Repair Manual Series

Printed in the

USA

reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage or retrieval system, without permission in writing from the copyright

All rights

holder.

ISBN1 56392 188 X Library of

Congress Catalog Card Number 97-70905

is made to ensure that the information in this manual is correct, no liability can be accepted by the authors or publishers for loss, damage or injury caused by any errors in, or omis-

While every attempt

sions from, the information given.

97 - 320

Contents Chapter About

this

Introduction

1

manual

1-1

How diesel

engines are different Glossary of terms Buying parts A place to work Tools and equipment Fasteners Component disassembly

1-1

1-2 1-3 1-4 1-5

1-35 1-39

Gasket sealing surfaces

1-39

Hose removal

1-39

tips

Automotive chemicals and lubricants

1-40

Safety

1-41

first!

1-42

Diesel engine troubleshooting

Chapter 2

GM

5.7L, 6.2L

and 6.5L

V8 engines Specifications

2-1

Introduction

2-3

Maintenance Cooling system Fuel system

system Emissions control systems In-vehicle engine repairs

Electrical

Chapter 3

2-3 2-13 2-16 2-45 2-83 2-119

Ford 6.9L and 7.3L engines

Specifications

3-1

Introduction

3-2

Maintenance Cooling system Fuel system Electrical system Emission control systems In-vehicle engine repairs

3-4

3-14 3-20 3-32 3-44 3-45

Engine overhaul procedures

Chapter 4

.4-1

Specifications

General information and diagnosis Engine overhaul - general information Compression check Engine removal - methods and precautions Engine - removal and installation Engine rebuilding alternatives Engine overhaul - disassembly sequence Cylinder head - disassembly Cylinder head - cleaning and inspection Valves - servicing Cylinder head - reassembly

Pistons/connecting rods - removal

Crankshaft - removal

Engine block - cleaning Engine block - inspection Cylinder honing

4-11

4-15 4-17 4-18 4-18 4-19 4-19 4-20 4-20 4-25 4-26 4-27 4-28 4-29 4-31

4-31

Pistons/connecting rods - inspection

4-33 4-34 Crankshaft - inspection Main and connecting rod bearings - inspection .... 4-34 4-35 Engine overhaul - reassembly 4-35 Piston rings - installation Crankshaft - installation and main bearing clearance check

oil

Rear main

oil

4-41

4-43

seal installation

Pistons/connecting rods - installation and rod bearing Initial

start-up

oil

4-43 4-46

clearance check

and break-in

after overhaul

HIQH PRESSURE INLET

LEAK-OFF PORT

SHIM

PRESSURE SPINDLE

NOZZLE NUT

^

PRESSURE SPRING INTERMEDIATE PLATE

NEEDLE VALVE

PINTLE NOZZLE

HEAT SHIELD

WAVE WASHER

Chapter

About

this

Introduction

1

the diesel engine uses compression ignition. Compression ignition occurs

manual

when The purpose

manual

you service and overhaul the Ford 6.9L and 7.3L light truck diesels and General Motors automobile and light pickup truck 5.7L, 6.2L and 6.5L diesel engines.

The manual Sections,

some

of this

is

is

to help

divided into Chapters. Each Chapter

which consist

of

of

consecutively

is

sub-divided into

numbered Paragraphs

(usually referred to as "Steps", since they're normally part of a procedure).

the material

If

is

basically informative in nature, rather than

a step-by-step

The first three Chapters contain material on servicing and maintaining Ford and General Motors engines, electrical, cooling and emissions systems. Chapter 4 covers the specifics of the overhaul procedure. Comprehensive Sections covering tool selection and usage, safety and general shop practices have been included. illustration" (in

parentheses),

is

used

in

the text to indi-

cate that a photo or drawing has been included to make the information easier to understand (the old cliche "a picture is worth a thousand words"

when

comes

how-to procedures). Also, every attempt is made to position illustrations directly opposite the corresponding text to minimize confusion. The two types of illustrations used (photographs and line drawings) are referenced by a number preceding the caption. Illustration numbers denote Chapter and numerical sequence within the Chapter (i.e., 3.4 means Chapter 3, illustration number four in order). The terms "Note", "Caution", and "Warning" are used throughout the text with a specific purpose in mind - to attract the reader's attention. A "Note" simply provides information required to properly complete a procedure or information which will make the procedure easier to understand. A "Caution" outlines a special procedure or special steps which must be taken when completing the procedure where the Caution is found. Failure to pay attention to a Caution can result in damage to the component being repaired or the tools being used. A "Warning" is included where personal is

especially true

it

to

can result the instructions aren't followed exactly as described. Even though extreme care has been taken during the preparation of

injury

this

for

if

manual, neither the publisher nor the author can accept responsibility in, or omissions from, the information given.

any errors

How diesel

engines are different

There are many

similarities

air in

opposed

compresses the enough (around 1000-degrees F) to ignite

gasoline engine ratios of 5:1 to 14:1

to

the cylinder

until

it's

when fuel is injected. A gasoline engine has

hot

both an ignition system and

The

duction system for controlling engine speed.

because

it

needs only the

the fuel at the precise

fuel injection

moment when

pump and

ignition

)

air/fuel

diesel

is

mixture

much

in-

simpler

injectors for delivering

can occur. An unrestricted

supply of

procedure, the Paragraphs aren't numbered.

The term "see

the extremely high compression ratio of the diesel engine (18:1 to

24:1 as

between diesel and gasoline engines but

air is supplied by the intake manifold. Another unique feature of the diesel engines covered by this manual is that an electric glow plug system operates when starting the engine and until combustion chamber temperatures sufficient to sustain self-ignition are reached. Starting fluid must never be used with the diesel engines covered by this manual, because the glow plugs remain hot when the intake valves are open and can ignite the fluid, causing a flame to travel back through the intake manifold. Personal injury and/or engine damage could

occur.

comes from a lower petroleum distillate than gasoline and pump and injectors, reducing wear in the engine. The cetane number of diesel fuel indicates it's ignition quality; the higher the Diesel fuel

it

lubricates the fuel

number, the faster

it

burns, making for easier starting and smoother run-

ning. Diesel fuel contains

more energy and burns more air per volume than

gasoline, which partially accounts for a diesel's greater efficiency.

however, several disadvantages to diesel fuel. It contains it's volitility is affected by temperature more than gasoline is, it absorbs moisture readily and it contains ten times more sulphur than gasoline. At lower temperatures (10-degrees F and below) number

There

are,

paraffins (waxes),

two diesel

fuel will

become cloudy (this is called the "cloud point") because

the pariffins crystalize, clogging the fuel

filter.

If

cold enough, the fuel can't

be poured or pumped ("pour point"), so different blends of fuel are required for summer and winter driving. Water in diesel fuel can corrode the injectors and encourage bacteria (which feed off the sulfur) to grow in the fuel, leading to contamination problems. The sulfur can also accelerate wear because it forms corrosive deposits in the engine. Consequently, devices such as water sensors and separators are used in diesel fuel systems and care must be taken to change the fuel filter and engine oil and filter on a regular basis. Gasoline engines use intake manifold vacuum to operate components such as the brake booster. Since diesel engines have unrestricted air intake, there is very little vacuum. Vacuum pumps are required to operate accessories.

makes the serv-

Diesel engines offer several advantages over gasoline engines, partic-

and repairing of a diesel engine unique. The diesel engines covered by this manual operate on the same four-stroke principle (intake, compression, power and exhaust) as most gasoline powered engines. But, instead of igniting the fuel and air in the cylinder during the third (power)

area of fuel efficiency, low-speed torque and reliability. One reasons diesel engines tend to get better mileage than gasoline engines is because they burn fuel more completely. Diesel fuel exhaust, when the engine is properly tuned, actually have fewer hydrocarbons and carbon monoxide than gasoline exhaust.

it's

the differences involved with the ignition of the fuel that

icing

stroke by introducing a spark from the spark plug as on a gasoline engine,

ularly in the

of the

"

-2

1

Chapter

Introduction

1

Glossary o( terms Delivery line* - Fuel lines used to carry fuel from the injection pump lo \t\9 iniector

A

Additive

material

their properties

added

such as

to fuels

and

lubricants,

viscosity, cetane.

designed

pour point,

to

improve

nozzles

Delivery valve - An injection line

pump valve that rapidly decreases miection

pressure to an achieve an abrupt fuel cutoff

at

the injector

film strength, etc.

Diesel fuel - A petroleum-based middle distillate suitable as a fuel for die-

Afterglow - The penod dunng which the glow plugs continue after the engine is started.

to

operate

sel engines.

Diffusion - Mixing the molecules of two gases by thermal agitation

Ambient

- Surrounding on

sides.

all

Diode - An

Atmospheric pressure - The weight pressure, the

pressure

air

at

sea

electronic device that permits current to flow through

it

can be mixed

Dispersant - Dispersing or scattenng in vanous directions; a state of matwhich finely divided particles of one substance (disperse phase) are in

another (dispersion medium) substance.

Dissipated - Scattered

B

Distributor injection

BDC

pressurizes fuel

- Bottom Dead Center

A

bacteha-killing

Blow-by - A leakage

compound used fuel in

in

diesel fuel.

tion

various directions.

pump

the exhaust.

end

Duration - The period

of the

to

by blowby allowing crankcase

bad

combuscomponents

oil in

rings, valve seals, or other faulty

the

while the engine

is

main

of time

Dynamic timing meter - A

chamber due

pump

injection

using pistons which

based on the

the proper cylinder

relative

Dribble - Insufficiently atomized fuel issuing from the nozzle at or immedi-

or loss of pressure past the piston into the crank-

smoke - Caused

- An

for injection in

ately following the

case Blue

in

port position of the rotating shaft in the hydraulic head.

smoke - Incompletely burned

Black

m one

ter in

suspended

air.

Biocide -

it

direction only.

level is 14.7 psi.

Atomization - Breaking up of the fuel into fine particles, so with

expressed as

of the air, usually

injection

phase.

dunng which anything

GM

diesel tool

used

lasts.

measunng

for

running by using a quartz sensor

in

timing

the combustion'

chamber

that measures the point of combustion and converts this to timdegrees of crankshaft rotation through the use of a magnetic crankshaft pickup and microprocessor.

ing in

BTU -

British

Thermal

Unit.

By-pass oil filter- An oil filter that removes soot and carbon by continual20 percent of the engine oil

ly filtering

Eccentric -

Calibration - Adjusting the rate, speed and timing of fuel delivery injection system. Calibration

oil

-

nozzles, meeting

Oil

which

SAE J967D

is

used

in

a tester

for

in

an

checking injection

One

circle within

another

circle not

having the

same center

Exhaust Gas Recirculation (EGR) - Redirecting exhaust gases back combustion chamber to reduce peak combustion temperatures.

into the

Exhaust Pressure Regulator (EPR) - A device for increasing exhaust backpressure at specific times to increase exhaust flow to the EGR valve.

specifications

Cetane number - The number indicating the ignition quality of diesel fuel, similar to the

octane rating

of gasoline.

Flash point - The temperature

Ceton filter - A sock-type filter in the fuel tank capable of wicking diesel fuel, but not water; keeps water from the rest of the fuel system until the sock is 90 percent submerged in water. Clearance volume - At Top Dead Center, the volume measurement combustion chamber

of

a

at

which

fuel self-ignites.

Fuel advance system - Advances fuel delivery during cold starts on Gf^ vehicles. Consists of a thermal-sensitive solenoid on the intake manifold which sends a signal to the HPCA terminal, which opens a ball-check valve on top of the injection pump housing. With pump housing pressure reduced, the timing mechanism has less resistance to overcome and operates earlier, advancing fuel delivery 3 degrees.

Cloud point - The temperature at which paraffin separate out of solution and start to crystallize.

crystals

in

diesel fuel

Fuel return line - The

back

Coalescing action - The process of smaller water droplets merging gether into larger droplets which takes place in a water separator.

it

begins

to

excess

fuel

from the injectors

pump.

to-

Compression ignition - The burning an air/fuel mixture in the combustion chamber by compressing sufficiently to raise its temperature above the flash point of the fuel and injecting into the combustion chamber so that it

fuel line that returns

to the fuel tank or inlet side of the injector

burn spontaneously.

Glow plug - An

electrical heating

device that helps diesel engines

start

and run smoothly when cold by creating heat in the pre-combustion chamber.

Compression ratio - The clearance volume of an engine cylinder divided

Governor - A device that controls the speed of an engine within specified

by

limits.

its

total

volume.

Control module - A device used when starting a diesel engine which conglow plug temperature, preglow time and afterglow time; also known as a controller.

trols the fast idle,

I

Injection lag -the time interval (usually expressed

in

crankshaft degrees)

Crankcase Depression Regulator (CDR) - A device which aids in the control of crankcase gases by maintaining a specific amount of vacuum in

between the nominal start of injection pump delivery and the actual start of

the crankcase.

Injection nozzles -

injection at the nozzle.

See

"Injector nozzles.

Chapter pump

Injection

A pump which

-

1

delivers fuel to the pre-combustion

chambers at a high pressure so the injector can overcome compression and combust during the Injection process.

pump governor - A device which controls fuel delivery to limit minimum and maximum engine speeds, as well as Intermediate

Injection the

Injection timing -

Injection

pump

The matching

of the

pump timing

mark, or the Injector

mechanism, to some index mark on the engine components, so that

Injection will

occur

advance

at the

fuel into the

proper time with reference to the engine cycle.

or retard

delivery cycle

Injector nozzles

in

Is

respectively an earlier, or

later, injection

reference to the injection cycle.

- Small spring-loaded valves

combustion chamber.

In-line fuel heater

- A 100-watt heater which

pump fuel pres-

Is

Integral to the fuel line.

keep paraffin crystals from The heater warms the fuel by 20 degrees.

the fuel prior to the

stopping fuel flow.

filter

to

leakage on a pop

GM Injection nozzle.

Pop tester - An injector testing tool used for measuring opening pressure, leakoff pressure

and spray patterns

of injectors

Positive Crankcase Ventilation (PCV) system -

case

ventilation that returns

where they are sent

to

A system for crankcrankcase blowby gases to the Intake manthe combustion chambers for reburning

Pour point - The temperature

which diesel

at

fuel

can no longer be

Pre-chamber- A precombustion chamber built Into the cylinder head that In the incoming air. Sometimes called a swirl chamber.

creates turbulence

Pre-glow - The period

injec-

of time

when the glow plugs are

heating to operat-

ing temperature.

Sock - The fuel Leak-off pressure - f^anufacturer-specified pressure used to test tor

Ventilation.

poured or pumped

Injector opening pressure - The point at which Injection

warms

- Positive Crankcase

Peak pressure period - The phase of diesel combustion lasting from about five degrees before top dead center to about 10 degrees after top dead center; the majority of diesel fuel burns during this period.

ifold

with nozzles which inject

sure overcomes nozzle valve-spring resistance, or combustion chamber pressure, so that fuel is Injected into the pre-combustion chamber.

This heat

PCV

Pencil-type injector - An early

throttle positions.

timing

1-3

Introduction

ran,

pick-up strainer

so water won't enter

tester.

Supply

until

in

the fuel tank.

the sock

The sock

is virtually

is

engulfed

made in

of sa-

water.

pump - A pump that transfers fuel from the tank and delivers

it

to

the injection pump.

M

Swirl

Manometer- instrument used for measuring the

"swirl."

pressure of liquids and

- Rotation of the mass of air as This is one form of turbulence.

it

enters the cylinder

is

known as

gases.

Micron - One-millionth

of

a meter.

Min/max governor - Controls the

Module -

Idle

speed and prevents overspeed.

Electronic control unit that controls the glow-plug system.

Moisture content - The amount

of

water contained

in

diesel fuel.

Thermal switch - A bimetal switch

that controls

glow plug operation.

Transfer pump - Part of the fuel Injection pump; boosts fuel pressure from around 20 psi to about 1 30 psi, depending on the pump and the engine speed.

N NOx - Oxides Number one

of nitrogen,

-

a

pollutant;

a component of diesel exhaust.

sometimes blended with number two diesel fuel to increase number one's energy and diesel fuel

Diesel fuel used

in

cold climates;

two's cold-weather performance.

Number two

diesel fuel

-

Diesel fuel used

in

moderate climates.

V Vacuum pump - A device for creating vacuum to power various systems such as power brakes and other components.

Vacuum regulator valve - A device for controlling vacuum from the vacuum pump to the transmission, cruise control and other components that need a regulated vacuum source based on Viscosity -

o Orifice

A

restriction to flow In

a

A

liquid's

throttle position.

resistance to flow.

line or tube.

w Water separator - A device Paraffin

- A semi-transparent, waxy mixture

principally from the distillation of

ane

for

removing water from the

fuel,

located

in

the fuel line of diesel engines.

of hydrocarbons, derived petroleum any hydrocarbon of the meth;

series.

White smoke - Unburned fuel emitted by the exhaust combustion chamber temperatures.

that indicates low

department prices. I^any auto parts stores and mail order houses offer complete engine kits, often at a considerable savings over individual

Buying parts

parts.

Commonly replaced engine tons, bearings, camshafts,

parts such as fuel

lifters,

timing chains,

filters, oil

piston rings, pis-

pumps and gaskets

are produced by aftermarket manufacturers and stocked by retail auto parts stores and mail order houses, usually at a savings over dealer parts

Less-commonly replaced items such as injectors and lines may not be same sources and a dealer service department may be your only option. Keep in mind that some parts will probably have may take several days to get your parts; order early. to be ordered, and available through these

it

1

-4

Chapter

Introduction

1

will make oil spills and dirt easier to remove arx) he

'.

^is^tsimfMik.

mm)

will

do)

Brass hammer Brushes (various sizes, for cleaning small passages Combination (slip-joint) pliers - 6-inch Center punch Cold chisels - 1/4 and 1/2-inch Combination wrench set (1/4 to 1-inch) Extensions - 1-. 6-, 10- and 12-inch E-Z out (screw extractor) set Feeler gauge set Files (assorted)

Floor jack

Gasket scraper

Hacksaw and assortment of blades Impact screwdriver and bits

1 .3

One quick way

to determine whether you're looking at a wrench is to read the information printed on the handle - if it says "chrome vanadium" or "forged," it's

quality

made

out of the right material

6

Chapter

1

Introduction

1

-7

Open-end wrenches can do several things other wrenches - for example, they can be used on bolt heads with limited clearance (left) and they can be used in tight spots where there's little room to turn a wrench by flipping the offset jaw over every few degrees of rotation 1 .5

can't

.4 The size stamped on a wrench indicates the distance across the nut or bolt head (or the distance between the wrench jaws) in inches, not the diameter of the threads on the fastener

1

there are overpriced tools with well-known brand names.

may buy what

On

the other

a reasonable value set of wrenches only to find they fit badly or are made from poor-quality steel. With a little experience, it's possible to judge the quality of a tool by looking at it. Often, you may have come across the brand name before and have a good idea of the quality. Close examination of the tool can often hand, you

looks

like

reveal some hints as to its quality. Prestige tools are usually polished and chrome-plated over their entire surface, with the working faces ground to

The polished finish is largely cosmetic, but does make them easy keep clean. Ground jaws normally indicate the tool will fit well on fasten-

size.

to

it

ers.

A

side-by-side comparison of a high-quality wrench with a

equivalent is an eye opener. material, often a

cheap The better tool will be made from a good-qual-

forged/chrome-vanadium steel

(see illustrabe kept as small and compact as possible. If, by comparison, the cheap tool is thicker and heavier, especially around the jaws, it's usually because the extra material ity

alloy

tion). This, together with careful design, allows the tool to

compensate for its lower quality. If the tool fits properly, this - is, after all, cheaper - but in situations where it's necessary to work in a confined area, the cheaper tool may be too bulky

is

needed

isn't

to

to

necessarily bad

it

fit.

1

.6

Box-end wrenches have a ring-shaped "box at each end permits, they offer the best combination of "grip" and strength

when space

"

Open-end wrenches the open-end wrench is the most common has a jaw on either end, connected by a flat handle section. The jaws either vary by a size, or overlap sizes between consecutive wrenches in a set. This allows one wrench to be used to hold a bolt head while a similar-size nut is removed. A typical fractional size wrench set might have the following jaw sizes: 1 /4 x 5/1 6, 3/8 x 7/1 6, 1 /2 x 9/1 6, 9/1 X 5/8 and so on. Typically the jaw end is set at an angle to the handle, a feature which makes them very useful in confined spaces; by turning the nut or bolt as far as the obstruction allows, then turning the wrench over so the jaw faces in the other direction, it's possible to move the fastener a fraction of a turn at a time (see illustration). The handle length is generally determined by the size of the jaw and is calculated to allow a nut or bolt to be tightened sufficiently by hand with minimal risk of breakage or thread damage (though this doesn't apply to soft materials like brass or aluminium). Common open-end wrenches are usually sold in sets and it's rarely worth buying them individually unless it's to replace a lost or broken tool from a set. Single tools invariably cost more, so check the sizes you're most likely to need regularly and buy the best set of wrenches you can afford in that range of sizes. If money is limited, remember that you'll use

Because

of

type of wrench.

1 .7

its versatility, It

Box-end wrenches are available

in

1

2

(left)

and 6-point

openings; even though the 12-point design offers twice as

(right)

many

first - it's less likely to strip off the corners of a nut or bolt head

wrench positions, buy the 6-point

1

-8

Chapter

-^

1

Introduction

-•

-

A -^

^

^ ^

»

-•

,1-.

_

^

-1-a^—

y

^ 1.8

Buy

a set of combination

wrenches from

1/4 to 1-inch

Adjustable wrenches can handle a range of fastener sizes good as single-size wrenches but they re handy for loosening and tightening those odd-sized fasteners for which you haven't yet bought the correct wrench 1.9

they're not as

open-end wrenches more than any other type good set and cut corners elsewhere.

it's

a good idea to buy a

Box-end wrenches Box-end wrenches (see 6-point (hex) or

1

illustration)

have ring-shaped ends with a

2-point (double hex) opening (see illustration). This al-

on the fastener hex at 15 (1 2-point) or 30-degree each tool has two ends of different sizes, allowing an overlapping range of sizes in a set, as described for open-end wrenches. Although available as flat tools, the handle is usually offset at each end to allow it to clear obstructions near the fastener, which is normally an advantage. In addition to normal length wrenches, it's also possible to buy long handle types to allow more leverage (very useful when trying to loosen rusted or seized nuts). It is, however, easy to shear off fasteners not careful, and sometimes the extra length impairs access. As with open-end wrenches, box-ends are available in varying quality, again often indicated by finish and the amount of metal around the ring ends. While the same criteria should be applied when selecting a set of box-end wrenches, your budget is limited, go for better-quality open-end wrenches and a slightly cheaper set of box-ends. lows the tool to

fit

(6-point) intervals. Normally,

if

if

When you use an adjustable wrench, make sure the movable jaw points in the direction the wrench is being turned (arrow) so the wrench doesn't distort and slip off the fastener head

1.10

Combination wrenches These wrenches (see illustration) combine a box-end and open-end same size in one tool and offer many of the advantages of both. Like the others, they're widely available in sets and as such are probably a betof the

ter

choice than box-ends only. They're generally compact, short-handled

tools

and are

well suited for tight

spaces where access

bits,

crow's

likely to slip is

feet, etc.

- are

and

the corners

limited.

extra-thick walls

Adjustable wrenches Adjustable wrenches (see illustration)

come

in

several sizes.

Each

size can handle a range of fastener sizes. Adjustable

wrenches aren't as as one-size tools and it's easy to damage fasteners with them. However, they can be an invaluable addition to any tool kit - if they're used with discretion. Note: If you attach the wrench to the fastener with the movable jaw pointing in the direction of wrench rotation (see illustration), an

effective

adjustable wrench

will

be less

likely to slip

and damage the fastener head.

The most common adjustable wrench is the open-end type with a set of parallel jaws that can be set to fit the head of a fastener. Most are controlled by a threaded spindle, though there are various cam and springloaded versions available. Don't buy large tools of be able to find enough clearance to use them.

this type; you'll rarely

Ratchet and socket sets Ratcheting socket wrenches (see illustration) are highly versatile. Besides the sockets themselves, many other interchangeable accessories - extensions, U-drives, step-down adapters, screwdriver bits, Allen

Buy six-point sockets - they're less and nuts. Don't buy sockets with - they might be stronger but they can be hard to use on

strip

available.

off bolts

recessed fasteners or fasteners in tight quarters. Buy a 3/8-inch drive for work on the outside of the engine. It's the one you'll use most of the time. Get a 1/2-inch drive for overhaul work. Although the larger drive is bulky and more expensive, has the capacity of accepting a very wide range of large sockets. Later, you may want to consider a 1 /4-inch drive for little stuff like ignition and carburetor work. Interchangeable sockets consist of a forged-steel alloy cylinder with a hex or double-hex formed inside one end. The other end is formed into the square drive recess that engages over the corresponding square end of it

various socket drive tools. in 1/4, 3/8, 1/2 and 3/4-inch drive sizes. A most useful for engine repairs, although 1/4-inch drive sockets and accessories may occasionally be needed. The most economical way to buy sockets is in a set. As always, quality will govern the cost of the tools. Once again, the "buy the best" approach is usually advised when selecting sockets. While this is a good idea, since the end result is a set of quality tools that should last a lifetime, the cost is so high it's difficult to justify the expense for home use. As far as acces-

Sockets are available

3/8-inch drive set

is

Chapter

Introduction

1

A typical ratchet and socket set includes a ratchet, a set of sockets, a long and a short extension, a universal joint and a spark plug socket

1.12

1.11

left

l

|P 1l l

| l|.UU|

-9

Lots of other accessories are available for ratchets: From speed handle and a 3/8-to-1/4-inch adapter

to right, a breaker bar, a sliding T-handie, a

Orrm "^

1

"

l

i

1.13

Deep sockets enable you

to loosen or

tighten an elongated fastener, or to get at a

''

.:

nut with a long bolt protruding from

it

«*

series go, you'll

need a

ratchet, at least

inch size) a spark plug socket and ,

one extension (buy a three or six-

maybe a T-handle or breaker bar. Other

desirable, though less essential items, are a speeder handle,

a U-joint, ex-

cial

to

for 14 millimeter spark plugs. They have rubber inserts spark plug porcelain insulator and hold the plug in the socket

deep socket

to protect the

avoid burned fingers.

tensions of various other lengths and adaptors from one drive size to another (see illustration). Some of the sets you find may combine drive sizes; they're well worth having

avoid being dazzled by the

if

you find the

number

right set at

a good

price, but

of pieces.

Above all, be sure to completely ignore any label that reads "86-piece Socket Set," which refers to the number of pieces, not to the number of sockets (sometimes even the metal box and plastic insert are counted in the

total!).

Apart from well-known and respected brand names, you'll have to take a chance on the quality of the set you buy. If you know someone who has a set that has held up well, try to find the same brand, if possible. Take a pocketful of nuts

and

bolts with

you and check the

fit

in

some

of the

sock-

Check the operation of the ratchet. Good ones operate smoothly and crisply in small steps; cheap ones are coarse and stiff - a good basis for ets.

guessing the quality

One

of the rest of the pieces.

about a socket set is the built-in facility for exbasic set, you can purchase extra sockets when necessary and replace worn or damaged tools. There are special deep sockets for reaching recessed fasteners or to allow the socket to fit over a projecting bolt or stud (see illustration). You can also buy screwdriver, Allen and Torx bits to fit various drive tools (they can be very handy in some applications) (see illustration). Most socket sets include a speof the best things

pansion.

Once you have a

1.14

Standard and Phillips bits, Allen-head and Torx drivers will versatility of your ratchet and extensions even further

expand the

1

-10

Chapter

1

Introduction

V h

Torque wrenches (click-type on left, beam-type on right) are the only way to

^.

1.15

accurately tighten critical fasteners like connecting rod bolts, cylinder head bolts, etc.

1.16

wrench

The deflecting beam-type torque is inexpensive and simple to use

just tighten the fastener until the pointer

points to the specified torque setting

1.17 "Click" type torque wrenches can be set to "give" at a pre-set torque, which makes them very accurate and easy to use

Using wrenches and sockets Although you may think the proper use of tools is self-evident, it's worth some thought. After all. when did you last see instructions for use supplied wrenches?

with a set of

Which wrench? an engine apart, figure out the best tool for the wrench for a hex-head fastener. Sit down with a few nuts and bolts and look at how various tools fit the bolt heads A golden rule is to choose a tool that contacts the largest area of the hex-head. This distributes the load as evenly as possible and lessens the risk of damage. The shape most closely resembling the bolt head or nut is another hex, so a 6-point socket or box-end wrench is usually the best choice (see illustration). f\/lany sockets and box-end wrenches have double hex (12-point) openings. you slip a 12-point box-end wrench over a nut, look at how and where the two are in contact. The corners of the nut engage in every other point of the wrench. When the wrench is turned, Before you

start tearing

job; in this instance the best

If

pressure

The impact driver converts a sharp blow into a twisting this is a handy addition to your socket arsenal for those fasteners that won't let go - you can use it with any bit that fits a 1.18

motion -

This

applied evenly on each of the six corners (see illustration). was previously rounded off. If so. the

is

fine unless the fastener head

is

be damaged and the wrench will slip. you encounter a damhead or nut, always use a 6-point wrench or socket possible. you don't have one of the right size, choose a wrench that fits securely and proceed with care. If you slip an open-end wrench over a hex-head fastener, you'll see the tool is in contact on two faces only (see illustration). This is acceptable provided the tool and fastener are both in good condition. The need for a snug fit between the wrench and nut or bolt explains the recommendation the wrench jaws, the bolt head to buy good-quality open-end wrenches. or both are damaged, the wrench will probably slip, rounding off and distorting the head. In some applications, an open-end wrench is the only possible choice due to limited access, but always check the fit of the wrench on the fastener before attempting to loosen it; it's hard to get at with a wrench, think how hard it will be to remove after the head is dam-

corners

aged

will

If

bolt

if

If

3/8-inch drive ratchet

Torque wrenches Torque wrenches (see illustration) are essential for tightening critical like rod bolts, main bearing cap bolts, head bolts, etc. Attempting an engine overhaul without a torque wrench is an invitation to oil leaks, distortion of the cylinder head, damaged or stripped threads or worse. There are two types of torque wrenches - the "beam" type, which indicates torque loads by deflecting a flexible shaft and the "click" type (see illustrations), which emits an audible click when the torque resistance reaches the specified resistance. Torque wrenches are available in a variety of drive sizes and torque ranges for particular applications. For engine rebuilding, to 150 ft-lbs should be adequate. Keep in mind that "click" types are usually more accu-

fasteners

rate (and

more expensive).

Impact drivers The impact driver (see illustration) belongs with the screwdrivers, but mentioned here since can also be used with sockets (impact drivers normally are 3/8-inch square drive). As explained later, an impact driver works by converting a hammer blow on the end of its handle into a sharp twisting movement. While this is a great way to jar a seized fastener loose, the loads imposed on the socket are excessive. Use sockets only with discretion and expect to have to replace damaged ones on occasion. it's

If

if

aged. is an adjustable wrench or self-locking plier/wrench Use these tools only when all else has failed. In some cases, a self-locking wrench may be able to grip a damaged head that no wrench could deal with, but be careful not to make matters worse by damaging

The

last

choice

(Vise-Grips).

it

further.

Bearing

it

in

mind the remarks about the correct choice

of tool in the first

place, there are several things worth noting about the actual use of the tool. First,

tener off

is

the

in for

make sure the wrench head is clean and undamaged.

rusted or coated with paint, the wrench won't

head and,

if

it's

rusted, apply

fit

some penetrating oil. Leave

a while before attempting removal.

If

the fas-

correctly. it

Clean soak

to

Chapter

Try to use a six-point box wrench whenever possible - its shape matches that of the fastener,

1.19

1

Sometimes

which means maximum grip and slip

may seem obvious, but take a close look at the fastener to be removed before using a wrench. On many mass-produced machines, one end of a fastener may be fixed or captive, which speeds up initial assembly and usually makes removal easier. a nut is installed on a stud or a bolt threads into a captive nut or tapped hole, you may have only one fastener It

If

on the other hand, you have a separate nut and bolt, you must hold the bolt head while the nut is removed. In some areas this can be difficult, particularly where engine mounts are involved. In this type of situation you may need an assistant to hold the bolt head with a wrench while you remove the nut from the other side. If this isn't possible, you'll have to try to position a box-end wrench so it wedges against some other to deal with.

If,

component to prevent from turning. Be on the lookout for left-hand threads. They aren't common, but are sometimes used on the ends of rotating shafts to make sure the nut it

doesn't this

come

loose during engine operation (most engines covered by

book don't have these types of fasteners).

the thread type can be checked visually.

If

Introduction

1

If

you can see the shaft end,

you're unsure, place your

-11

Open-end wrenches contact only two sides of the fastener and the jaws tend to open up when you put some muscle on the wrench handle - that's why they should only be used as a last resort

a six-point tool just

1.21

doesn't offer you any grip when you get the wrench at the angle it needs to be in to loosen or tighten a fastener - when this happens, pull out the 12-point sockets or wrenches - but remember: they're much more likely to strip the corners off a fastener

(or socket)

minimum

.20

1

Using sockets to remove hex-head fasteners is less likely to result in than if a wrench is used. Make sure the socket fits snugly over the fastener head, then attach an extension, if needed, and the ratchet or breaker bar Theoretically, a ratchet shouldn't be used for loosening a fas-

damage

tener or for

final

tightening

because the ratchet mechanism may be over-

loaded and could slip. In some instances, the location of the fastener may mean you have no choice but to use a ratchet, in which case you'll have

be extra careful. Never use extensions where they aren't needed. Whether or not an extension is used, always support the drive end of the breaker bar with one

to

hand while turning it with the other. Once the fastener is loose, the ratchet can be used to speed up removal.

Pliers

Some tool only

need a

manufacturers

make 25

fraction of this selection

or 30 different types of pliers. You (see illustration). Get a good pair

the threads and see which way you have to turn your hand "unscrews" from the shaft. If you have to turn your hand counterclockwise, it's a conventional right-hand thread. Beware of the upside-down fastener syndrome. If you're loosening a fastener from the under side of a something, it's easy to get confused about which way to turn it. What seems like counterclockwise to you can

thumbnail

so your

in

nail

be clockwise (from the fastener's point of view). Even after years still catch you once in a while. In most cases, a fastener can be removed simply by placing the Occasionally, though, the wrench on the nut or bolt head and turning condition or location of the fastener may make things more difficult. Make sure the wrench is square on the head. You may need to reposition the tool or try another type to obtain a snug fit. Make sure the engine you're working on is secure and can't move when you turn the wrench. necesfor you. Position yourself so you can sary, get someone to help steady get maximum leverage on the wrench. If possible, locate the wrench so you can pull the end towards you. If you have to push on the tool, remember that may slip, or the fastener may move suddenly. For this reason, don't curl your fingers around the handle or you may crush or bruise them when the fastener moves; keep your hand flat, pushing on the wrench with the heel of your thumb. If the tool digs into your hand, place a rag between it and your hand or wear a heavy glove. the fastener doesn't move with normal hand pressure, stop and try to figure out why before the fastener or wrench is damaged or you hurt yourself. Stuck fasteners may require penetrating oil, heat or an impact easily of

experience, this can

it.

If

it

it

If

driver or air tool.

A typical assortment of the types of pliers you need to havein your box - from the left: diagonal cutters (dikes), needle-nose pliers, channel lock pliers, vise-grip pliers, needle-nose vise grip pliers

1.22

1

-12

Chapter

Introduction

1

# :c)

To adjust the jaws on a pair of vise-grips, grasp the part 1 .23 you want to hold with the jaws, tighten them down by turning the knurled knob on the end of one handle and snap the handles together - if you tightened the knob all the way down, you'll probably have to open it up (back it off) a little before you can close the handles

1.24

If

you

and careful, most fasteners can be removed with vise-grips

re persistent

Screwdrivers Screwdrivers (see illustration)

come

in

a wide variety of sizes and

Craftsman on up

is fine. But don't buy screwbucks at discount tool stores. Even if they look exactly more expensive brands, the metal tips and shafts are made with inferi-

price ranges. Anything from driver sets for ten like

or alloys of slip-joint pliers for general use. for

A

pair of

is

essential for eiectncal

go - when locked

handy

A

set of diagonal wire cutters pulling out cotter pins. Vise-

Grips are adjustable, locking pliers that grip a fastener firmly let

is

work and

reaching into hard-to-get-at places.

(dikes)

needle-nose models

into place. Parallel-jaw,

- and won't

adjustable pliers have angled

jaws that remain parallel at any degree of opening. They're also referred to as Channel-lock (the original manufacturer) pliers, arc-joint pliers and water pump pliers. Whatever you call them, they're terrific for gripping a big fastener with a lot of force. Slip-joint pliers have two open positions; a figure eight-shaped, elongated slot in one handle slips back-and-forth on a pivot pin on the other handle to change them. Good-quality pliers have jaws made of tempered steel and there's usually a wire-cutter at the base of the jaws. The primary uses of slip-joint pliers are for holding objects, bending and cutting throttle wires and crimping and bending metal parts, not loosening nuts and bolts. Arc-joint or "Channel-lock" pliers

have

parallel

jaws you can open

to

various widths by engaging different tongues and grooves, or channels, near the pivot pin. Since the tool expands to fit many size objects, it has

countless uses for engine and equipment maintenance. Channel-lock pliers come in various sizes. The medium size is adequate for general work; small and large sizes are nice to have as your budget permits. You'll use all three sizes frequently.

Vise-Grips (a brand name) with curved jaws

small one falls

if

come

in

various sizes; the

medium

size

best for all-around work. However, buy a large and possible, since they're often used in pairs. Although this tool is

somewhere between an adjustable wrench, a pair of pliers and a por-

table vise,

it

can be invaluable

for

loosening and tightening fasteners -

it's

the only pliers that should be used for this purpose.

damaged heads (see illustraremoving fasteners that've been rounded

signs enable the tool to grip firmly even on off

by

badly-fitting

wrenches.

As the name suggests, needle-nose signed for reaching into holes and other

pliers

have

aren't properly heat treated.

The important they really do slot in

long, thin

jaws de-

Most needlethe base of the jaws.

restricted areas.

nose, or long-nose, pliers also have wire cutters at Look for these qualities when buying pliers: Smooth operating handles and jaws, jaws that match up and grip evenly when the handles areclosed, a nice finish and the word "forged" somewhere on the tool.

They

usually

bend the

first

time

thing to

come

in

any screw has

remember when buying screwdrivers

sizes designed to

definite

fit

is

that

different size fasteners.

The

dimensions - length, width and depth. Like

a bolt head or a nut, the screw slot must be driven by a tool that uses of the available

bearing surface and doesn't

slip.

all

Don't use a big wide

blade on a small screw and don't try to turn a large screw slot with a tiny, narrow blade. The same principles apply to Allen heads, Phillips heads, Torx heads, etc. Don't even think of using a slotted screwdriver on one of

these heads!

The jaw opening is set by turning a knurled knob at the end of one handle. The jaws are placed over the head of the fastener and the handles are squeezed together, locking the tool onto the fastener (see illustration). The design of the tool allows extreme pressure to be applied at the jaws and a variety of jaw detion). Vise-Grips are great for

and

you apply some serious torque. A screwdriver consists of a steel blade or shank with a dnve tip formed at one end. The most common tips are standard (also called straight slot and flat-blade) and Phillips. The other end has a handle attached to it. Traditionally, handles were made from wood and secured to the shank, which had raised tangs to prevent it from turning in the handle. Most screwdnvers now come with plastic handles, which are generally more durable than wood. The design and size of handles and blades vary considerably. Some handles are specially shaped to fit the human hand and provide a better grip. The shank may be either round or square and some have a hexshaped bolster under the handle to accept a wrench to provide more leverage when trying to turn a stubborn screw. The shank diameter, tip size and overall length vary too. As a general rule, it's a good idea to use the longest screwdriver possible, which allows the greatest possible leverage. If access is restricted, a number of special screwdrivers are designed to fit into confined spaces. The "stubby" screwdriver has a specially shortened handle and blade. There are also offset screwdnvers and special screwdriver bits that attach to a ratchet or extension.

And

punches! This kind

don't use your screwdrivers as levers, chisels or of

abuse turns them

into very

bad screwdrivers.

Standard screwdrivers These are used to remove and

install conventional slotted screws and a wide range of sizes denoting the width of the tip and the length of the shank (for example: a 3/8 x 10-inch screwdriver is 3/8-inch wide at the tip and the shank is 1 0-inches long). You should have a vanety of screwdrivers so screws of various sizes can be dealt with without damaging them. The blade end must be the same width and thickness as the screw slot to work properiy, without slipping. When selecting standard

are available

in

screwdrivers, choose good-quality tools, preferably with chrome moly, forged steel shanks. The tip of the shank should be ground to a parallel, flat profile (hollow ground) and not to a taper or wedge shape, which will

tend to twist out of the slot

when pressure

is

applied (see illustration).

Chapter

Introduction

1

1

-13

Misuse of a the screwdriver blade shown is both loo narrow and too thin

and

slip or

will probably break off

no

The left-hand example shows a The right-hand drawing shows a damaged tip

snug-fitting tip

which

when 1

will twist

pressure

is

out of the slot applied

Standard screwdrivers - wrong fit in screw slot

.26

size (top), correct 1

.25

Screwdrivers

come

in

myriad

lengtlis, sizes

(center)

and styles

All screwdrivers wear in use, but standard types can be reground to shape a number of times. When reshaping a tip, start by grinding the very end flat at right angles to the shank. Make sure the tip fits snugly in the slot of a screw of the appropriate size and keep the sides of the tip parallel. Remove only a small amount of metal at a time to avoid overheating the tip and destroying the temper of the steel.

driver

Phillips

of

snug.

If

the

fit

is

(bottom)

good, you should be able to angle

down almost vertically without the screw slipping off the tip. Use only screwdrivers that fit exactly - anything else is guaranteed to chew out the screw head instantly.

The idea behind all cross-head screw designs is to make the screw and screwdriver blade self-aligning. Provided you aim the blade at the center

screw head,

it'll

engage

correctly, unlike conventional slotted

makes the screws suitable for machine installation on an assembly line (which explains why they're sometimes so tight and difficult to remove). The drawback with these screws is the driving tangs on the screwdriver tip are very small and must fit very precisely in the screw head. If this isn't the case, the huge loads imposed on small flats of the screw slot simply tear the metal away, at which point the screw ceases to be removable by normal methods. The problem is made worse by the normally soft material chosen for screws. screws, which need careful alignment. This

screws are sometimes installed during

initial

assembly with air

and are next to impossible to remove later without ruining the heads, the wrong size screwdriver is used. And don't use other types cross-head screwdrivers (Torx, Posi-drive, etc.) on Phillips screws -

tools

particularly

is

tip

the blade

of the

Phillips screwdrivers

and fastener

and worn

if

they won't work.

The only way to ensure the screwdrivers you buy will take a couple of screws with you to

make

sure the

fit

fit

properly,

is

to

between the screw-

\

\\

1 .27 The tip size on a number from 1 to 4, with

Phillips screwdriver is indicated 1

the smallest

2; right

-No.

(left

- No.

1

;

by a center - No.

1.28

New (left) and worn

(right) Phillips

screwdriver tips

3)

J

-14

1

Chapter

1

Introduction A bail puen hammer has a head with a conventional cylindrical lace one end and a rounded ball end at the other and is a general-purpose has a shorter necK than a daw tool found in almost any type of shop hammer and the face is tempered for striking punches arxJ chisels A fairty large hammer is preferable to a small one Although it's possit>te to find small ones, you won't need them very often and s much easier to control the blows from a heavier head As a general rule, a single 1 2 or 1 6 ounce hammer will work for most )obs, though occasionally larger or smaller ones may be useful. A soft-face hammer is used where a steel hammer coukj cause damage to the component or other tools being used A steel hammer head might crack an aluminum part, but a rubber or plastic hammer can be used with more confidence Soft-face hammers are available with interchange able heads (usually one made of rubber and another made of relatively hard plastic). When the heads are worn out, new ones can be installed finances are really limited, you can get by without a soft-face hammer by placing a small hardwood block between the component and a steel hammer head to prevent damage. Hammers should be used with common sense; the head shoukj stnke the desired object squarely and with the right amount of force For many jobs, little effort is needed - simply allow the weight of the head to do the work, using the length of the swing to control the amount of force applied take With practice, a hammer can be used with surpnsing finesse, but at

It

^

A

it

START

FAST IDLE SOLENOID

2.95 System No. 1 uses eight 12-voit, 85-watt slow-glow plugs controlled by an electronic module (1978 Oldsmobile 88 and 98, 1979 Olds Cutlass and early 1979 Olds 88 and 98)

turns on the Start light. If the ignition remains in the "Run" position from two to five minutes, the glow plugs and indicator lights are shut off to pre-

vent battery discharge.

direct current to the plugs.

Once the engine starts, the Start light goes off, but the glow plugs stay on for about the same length of time as the pre-glow period. This is called

the engine.

the "after-glow" period. After-glow

is

needed

to maintain

enough heat

The module

in

el; it's

the prechambers to keep the engine running smoothly. During the after-

pump. A two-amp diode

in the charging circuit (behind the instrucharging-system "feedback" to the fuel solenoid when the engine is turned off, which prevents engine run-on. When you turn on the ignition switch, two glow-plug relays (mounted on the firewall)

cluster) prevents

I -=.

to start

The module has several purposes:

It

provides a ground

b)

It

times

how

circuit for

long the Wait

the Wait and Start

light

lights.

should stay on after receiving the

c)

It

provides the ground

d)

It

provides the timing

circuit for

the glow-plug relays.

circuit for the

glow-plugs' after-glow period

goes off. e) It provides a ground circuit for the fast-idle solenoid. As a general rule, never replace the module until you've systematically eliminated all other circuits and components as potential problems. The thermistor (see illustration) senses engine coolant temperature. It's located in the right (passenger's side) front comer of the intake manifold. The thermistor enables the module to measure the length of the preglow period and energizes/de-energizes the fast-idle solenoid.

Start position; voltage to the fuel solenoid starts fuel flowing inside the in-

ment

you when

an electronic device located under the instrument pan-

a)

after the

module and the fuel solenoid. Voltage to module tells the module that the ignition switch has been turned to the

jection

tell

signal from the thermistor.

thestarter solenoid, the control

the

Start lights

usually taped to the main wire harness about eight inches from the

fuse block.

glow period, charging voltage is sent to the module; nine or more volts tells the module that the engine is running - the charging light then goes off. If the engine doesn't start - and the ignition switch is still in the "Run" position with the charging light still on - the module starts the entire process over again after a two to four second delay. When you turn on the ignition switch, it directs battery current to

is

The Wait and

Wait

light

y—

MHERT

MnERY IPWll

I

r I

32

WESEL ELECTROWCS MOnULE

T

tU

LjtL'i^r

I

Vr-^

FUSIBLE WIRES

GLOW PLUG RELAYS

RELAY

CONTROL

>

SOUO STAn

^^HtltlL

WAIT LAMf

CONTROL

ENGINE

RUNNING

*>

SIGNAL

THERMSTOR

:»^— I

^

LiUXiUlL ^t

'

l«l»

'>MI>lfelow 20-degrees F, and open above 25-degrees F, opens below

switch

1

If

1

1

20-degrees

F.

remove and replace

and 6.5L V8 engines

5.7L, 6.2L

isn't clK:kir>g. check the thermal controMer artd glow plug Unplug the connector at the therrnal corriroHer Connect one end of the test light to ground With the ignition m Run. check lor voNege

7

the

If

the relay

relay circuit

M

it

follows:

Condition 5: When the engine is cold, doesn't start (even though the Wait light appears to be okay - it goes on. then oft) it

the pink wire

there's

if

pump with the ignition

no voltage.

the test

If

in

Check

9

Run position Repair comes on. turn off the

check

for

wires)

If

Using a self-powered test light, check for continuity through the ground If there is no continuity, replace the fuel solenoid. With the ignition in the Run position, and the engine stopped, listen to 3 the glow plug relay. It should be clicking on and off. If it's clicking, go to step 4; if it isn't clicking, proceed to step 7. 4 If the relay is clicking, turn off the ignition. Unplug the connectors to all ignition.

prevent accidentally energizing the plug.

connect all the connectors to their respective glow plugs. If the test light doesn't come on, touch the connector 5 block or plug.

6

If

If

some

the

all

other ground.

light

doesn't

If

come

the

light

then

comes

to the

If

off

and

Condition

If

the

in

If

of the test light to t

glow plug relay

If

the

1

2-volts at the t>attery

light

comes on

6:

The engine stays on off.

the connector

fallen into the

all

gk>w

Touch the

replace the tt^ermal

the connector at

and note whether the

fast idle solenoid

extends

If

the sole-

binding.

If

the linkage

is

okay, replace the solenoid

Check the continuity of the engine temperature switch with a selfpowered test light There should be continuity below 1 20-degrees F and no continuity above 1 20-degrees F Replace the switch it's bad. 2

engine

if

7: The Wait light pulses slowly on and off Hook up a test light between the white and yellow wires light control relay. the test light is on when the Wait light is when the Wait light is on. replace the Wait light control relay

Condition 1

combustion

If

V8

FAST

GLOW

V8

SLOW GLOW 26 ± 4

LH BANK AMMETER READING LESS THAN NORMAL

AMMETER READING NORMAL

RH BANK AMMETER READING LESS THAN NORMAL

more glow plugs on LH bank not Check individual glow plug leads by connecting ammeter in series

Glow plug system operating normally

or

more glow plugs on RH bank not Check individual glow plug leads by connecting ammeter m series

One

or

operative

operative

BRN wire that feeds glow plug Operate the system and note the reading on ammeter Repeat procedure tor each glow plug Each individual wire should have a reading of approximately 14 amps for a fast glow plug and 7 amps for a slow glow plug

with

BLK wire that feeds glow plug Operate the system note the reading on ammeter Repeat procedure lor each glow plug Each individual wire shouk] have a reading of approximately 14 amps for a fast glow plug and 7 amps for a slow glow plug

with

READINGS NORMAL

Glow Plugs and Harness

READINGS LESS THAN NORMAL

OK

On

those cylinders with less than normal readings, ciieck for continuity through the harness by disconnecting the lead and connecting a 12 volt test light from the

connector to ground Operate the glow plug system

TEST LIGHT LIGHTS

t)anks at

on.

btacfc

on, replace the glow

GLOW

tx>iri

and

noid doesn't extend, check the throttle linkage or the solenoid plunger for

56 ± 4

ammeter read

.

Run Unplug

42 ± 4

in line

comes

fast idle

turn the ignition to

NORMAL AMP READINGS

using an

rtole

cold, re-

the engine temperature switch Touch the jumper to the two terminals on

re-

V6

*lf

is

repair the yellow wire tjetween the

Connect an ammeter m series (induction type meter may also be used)' with DK BLU wire leading from the Glow Plug Relay to the LH bank ol glow plugs Operate the system and note the ammeter reading Repeat the procedure lor the BLK wire leading trom the Glow Plug Relay to the RH bank ol glow plugs Operate the system and note the reading

One

the light

the glow plug relay (red to blue

doesn come on.

light

With the engine

1

chamber, remove the cylinder head and clean out the debris.

FAST

comes on.

the ertgme

controller

on, replace the wire to the glow plug.

a glow plug has broken

II

the contacts are shorted, replace the relay Also replace

controller and the

eight glow plugs are open-circuited, then replace the thermal

controller.

the bght

voltage through the orange wire

Connect one end

1

test light

When you're finished testing,

for

shorted contacts

yellow wire

between the rear post (blue and black wires) of the glow plug relay and ground. Touch each connector to the spade terminal of its respective glow plug. If the test light comes on. the glow plug and harness lead are good. Test all the glow plugs this way. Make sure you set aside each connector after testing its plug to Connect a self-powered

It

closed

plugs and the thermal controller

fuel solenoid to

eight glow plugs.

is

place the switch

the

light

voltage through the brown wire

for

whether the coolant temperature switch

1 Is the engine cranking speed at least 1 00 rpm'' If it isn t. check battery voltage with a voltmeter - it should be 12 4 volts with the ignition off 2 Using a test light, check for voltage at the pink wire lead at the fuel

solenoid of the injection

Check

8

once Do not

2.109

cut wire

Harness

Preliminary

OK

Replace glow plug

ammeter

TEST LIGHT DOES NOT LIGHT WHEN GLOW PLUGS ARE OPERATING

Repair or replace harness RetesI glow plug for proper operation

test (5.7L engines)

at the off.

Wait

and

off

GM

Chapter 2

5.7L, 6.2L

2-55

and 6.5L V8 engines

Glow Plug Control System Diagnosis Index INSTRUCTIONS: The exact condition as outlined must exist for the charts to be of value. A situation found in the system that does not agree with the chart means that the chart can not be followed. Charts are in alphabetical order on the pages following.

Engine

will

not start, glow plug relay buzzing

Engine

will

not start, wait

Engine

starts

hard or not

Engine does not

Engine hard

Engine does not

>-o

Engine

Hard

at

start

all

may

not

come

S

A

on).

- normal

wait

Chart

Chart

glow plugs turn

start,

light

off

glow plugs not on

start,

Batteries run down, glow plugs

wait light

do not shut

after

light

on continuously, glow plug relay on

Wait

light

stays on after engine starts.

engine starts (fuse

ok).

S

P

S

A

for first time,

then

off.

S

light

Wait

light

Wait

light

does not

Wait

light

does not come on, but engine

Wait

light

does not

starts after

on

A

Allied

P

Packard Electric Glow Plug System Slow Glow Plug System

light

turns

on cold engine, glow plugs

after

engine

Chart

V

Chart

C

Chart

D

starts, or after

light

Chart S

starts after

normal wait period.

N

Prelim.

Prelim.

Chart

M

Chart

S

S

Chart

G Chart

starts.

P Chart

off.

off in

the normal time period.

S

Chart

W

Glow plug

H

A

2-5 minute emergency shutdown.

N

Chart X

A

on and goes

S

Chart J Chart Q

P

P

engine

Chart

Chart P

P

Chart

S

Chart

Glow Plug System

2.110a

Prelim.

Chart T

does not come on, but wait

Start light stays

B

A

Start light

start light

after

glow plugs operate ok.

does not come on.

Chart

Chart L

normal wait period.

glow plug relay does not operate.

Start light

Immediate

Chart

P

(bulb ok) glow plug relay operates normally, engine starts ok.

Wait lamp operates satisfactory, then comes on

S

off.

on continuously, glow plug relay operates normally, engine

start light, wait light stays on,

M

Chart F

on continuously, glow plug relay on - then quickly

Wait

Chart

R

P

light stays on, or (for 1979 system) both wait and start lights stay on after engine starts (start A flashes with glow plug pulses, then stays on steadily after engine starts).

No

Chart

A

Prelim,

Wait

light,

S

S

2-5 minutes (emergency shut down).

and glow plugs normal.

K

Chart L

too soon after engine starts (afterglow time).

off after

Wait

light

R

P

operation.

Chart

Chart E

S

times (causing rundown batteries).

all

start,

or

P

does not operate.

P

Engine njns rough on cold

Engine won't

may

(glow plug(s) inoperative).

Engine runs rough on cold

at

relay

(glow plugs not on long enough).

starting, or will not start cold

Glow plugs on

Chart

P

not start cold.

will

P

on continuously, glow plug

start cold {wait light

to start cold.

lijUJ

Q.

light

^%

^^J"

CONDITION

control system diagnosis index (5.7L engines)

1

U

2-56

Chapter 2

GM

5.7L, 6.2L

and 6.5L V8 engines

CHART A

ENGINE DOES NOT START PLUG(S) INOPERATIVE

GLOW

MOTt:

T>««

«« mom

2-9

mnum toi

arcuM b*4or* *m tnxgancy down oooura Tivrang tw igniBan

c^aclung •hul

twltc^Oll•ndb•CtlOn«Mlr•••(•yM•nl H

Turn ignition switch to "RUN" (see note). Connect 12 volt test light to ground and touch test light probe to one glow plug terminal on nght bank and one on left bank. Test light should be on both tests

OR

plug

opx aaon and dwoonn«cw\_^ f

'

,

fUf

I

Abl

SO

btU

l[)l

i

OLOw piua CONTROLIER

I

MOTI TERMINAL RlK GHO b

l-«@»

SPLICES INTO TERMINAL • RLK AT S^LICf IW) THEV THEN

y

AMP GAU IDLE

TEMPERATUftE

FAST IDLE 8. COLD ADVANCE TEMP SW OPENS AT gbof 10

GRD AT ENG

INHIBIT SWITCH 125

COLO AOV SOl

FUSE

~

OHMS EPRION

'w/(.AUGES

CLOSED

I

•==• BAT

I

—

4 I

II'

ISOL S]

'U/vv •

OPEN

I

j«"'jl(.«(ON_?l"

.Ho" I

TLi.

'sot

lON (

8° 550

^*_j

I

THHOIUt SWITCH

L

f)

ONLY

NOTE THE TCC SOL SWITCH WILL OPEN AT WO T ONLY WHEN THE SWITCH IS NOT ATTACHED TO THE INJ PUMP

CONTROLLER TERMINAL LOCATIONS

2.114

Typical electrical circuit for

System No. 4

1982 C, K,

PTRUCK

(early): Fast-glow,

thermal controller (1982 through 1984 6.2L engines)

"D"

TRUCK CUCV

BATTERY & CABLES

GLOW PLUG

GLOW PLUG

RELAY

RELAY ASM

GLOW PLUG WIRING WIRING HARNESS

2.115

Glow plug

relay locations (1982 through 1984 6.2L engines)

Chapter 2

GM

5.7L, 6.2L

2-73

and 6.5L V8 engines

RTV sealant over the hole from entering the controller

If

now

at the

No. 2 pin to prevent any more dirt or water

recycles correctly, the problem

is

solved:

if

it

was probably excessive Replace the con nector. The two wires from the No 5 and No. 6 pin positions are ground wires. The ground connection is at the rear of the right head on a stud which also grounds the body ground strap. The stud is on the opposite side of the engine from the controller. Make sure the ground connection is sedoesn't, corrosion of the pins

cure

Diagnosing System No. 4 problems (1982 through 1984 models with 6.2L engines)

4F«^

You'll need the following tools to perform the diagnostic procedures contained below - a digital multimeter, a self-powered test light, a 1 2-volt test light and a volt-ampere tester with an inductive pick-up. You'll need

measure extremely low voltages without burning the electronic controller. The self-powered test light is necessary for checking glow-plug continuity in circuit checks where no voltage can be applied. The 1 2-volt test light is handy for checking normal 1 2-volt circuits. You need the volt-amp tester for measuring amperage draw between left and right glow-plug banks. Note: To get a good grasp of how System No. 4 works, read through the entire diagnostic section before tackling any troubleshooting procedures. It s essential that you understand the interrelatedness of the various system components before the digital multimeter to out the delicate circuits

2.116 The glow plug controller on early 1982 6.2L engines has a small hole in the top through which dirt and moisture enter and upset controller operation

trying to track

in

down a problem.

Preliminary checks Note:

Make

sure you read

this entire section,

steps

1

through

5,

before

proceeding.

Controller contamination

on early 1982 models with 6.2L engines

On early 982 models with 6.2L engines, there's a hole at the no. 2 pin 1

engine wire harness connector for the controller (see illustration). nnoisture can enter this hole and corrode the pin connections, causing the controller to malfunction. If you've got an early 1982 6.2L model, and have experienced poor starts, burned glow plugs, etc., remove the connector from the controller of the Dirt

and

and inspect it for moisture and dirt. Clean the pin areas on the controller and the connector and reinstall the connector. Apply a small amount of

1

Check the operation

Run

position, the

of the glow plugs. With the ignition switch in the glow plugs light should come on, and stay on, for 8 to 1 seconds. When it goes out, start the engine. The light should then cycle a few times and go out. If the system doesn't cycle, or continues to cycle, repairthe glow-plug system. Note: All 1984 through 1989systems have a temperature inhibit switch which prevents glow-plug operation when the engine coolant temperature is above 1 25-degrees F. 2 Verify that all the glow plugs are working correctly by performing a preliminary diagnosis with an ammeter (see illustration). If the glow plugs

Connect an ammeter

in series (induction type meter may also be used)* with OK red wire leading from the Glow Plug Relay to the LH bank of glow plugs Operate the system and note the ammeter reading Repeat the procedure tor the red wire leading from the Glow Plug Relay to the RH bank of glow plugs Operate the system and note the reading

VEHICLE MODEL NORMAL AMP READINGS

GVan

LH BANK AMMETER READING LESS THAN NORMAL

or more glow plugs on LH bank not operative Check individual glow plug leads by conneclmg ammeter in series with GRN wrre that (eeds glow plug Operate the system and note the reading on ammeter Repeal procedure for each glow plug Each individual wire should have a reading ol approximately

One

Preliminary diagnosis of the glow-plug system with an ammeter

2.117

(1982 through 1984 6.2L engines)

P

cucv

55 MIN.

35 MIN

C. K.

50 I^IN

AMMETER READING NORMAL

RH BANK AMMETER READING LESS THAN NORMAL

or more glow plugs on RH bank not operative Check individual glow plug leads by connecting ammeter m series with GRN wire that feeds glow plug Operate the system, note the reading on ammeter Repeat procedure for each gtow plug Each individual wire should have a reading

One

Glow plug operating normally

C K, P =14 amps GVan = 13 amps CUCV = 9 amps

ot

approximately

READINGS LESS THAN NORMAL

READINGS NORMAL

On those

Glow Plugs and harness OK

cylinders with less ihan

normal readings, check for continuity through the harr^ess by disconnecting the lead and connecting a 12 voM test light from the connector to ground Operate the glow plug system

TEST LIGHT LIGHTS '

MTiS! VAT 40

WHEN GLOW PLUGS ARE OPERATING

TEST LIGHT DOES NOT LIGHT

(

Harness

OK

Replace gtow plug

Repair or replace harness Retest glow plug for proper operation

2-74

Chapter 2

are working correctly, the problem ing correctly, reter to the

is

somewhere else,

it

GM

5.7L, 6.2L

work

ttiey re not

ue cycling on and

accompanying troubleshooting charts (see illus-

gine

Check

all

fuses, bulbs

and grounds before you replace any compo

Make

and

dry.

5

Finally,

sure that no wires are exposed and

all

Is

connections are clean

The

Is

internal circuits

- a pre-glow

Engine does not

GLOW 1

not

Check

for

Check

open

circuit in

wire from controller to splice 503.

If

lt>e cir

right controller?

controller tor 6

the engine timing advanced? injection

pump timing causes higher

will

No current at one or more wire* One or mora glow plugs not functional (Appro IS ampt p«f

glow plug current using clamp on ammeter (Snapon MT-552 or equivalent) clamp around dark green wire leading to each plug.

Current all 8 wires and plugs cycle on and off Glow plug system Is OK, check for other cause of hard starting.

GRN

On and ttie er^ne oft

2 Battery voltage Is 10 volts or more when glow plugs cycle on 3 Cranking speed OK |100 RPM or more)

or

,

8 wires, but glow, come on once.

*ith the ignition turned to

ELECTRICAL SYSTEM DIAGNOSIS

start cole

OK

all

Oi arx) lt)« enlight will ONLY

turned to

t

PLUGS' lamp may come on Is

il

than normal cylincause the glow plugs to fail When the timir»g is advanced, some of the glow plugs - but not all eight - won operate A normal looking glow plug which is electncally open, or has a small blister, could be due to a glow-plug or a system default. But when a glow plug tip has been burned off, its most likely the result of advanced engine timing.

Fuel system ct^ecked

and

Key

controlling the

der temperatures, which

— 6.2 L DIESEL GLOW PLUG

may

is

Advanced fuel

timer,

an after-glow timer and a circuit breaker. Failure of the pre-glow timer will cause the circuit breaker to take over. During a cold start, you can determine whether the pre-glow timer or the circuit breaker is operating the glow plugs by watching what the glow plugs light on the dash does. If the pre-glow timer is working properly, the glow plugs light will contin-

Chart #1

igniiion

working, the glow plugs

values.

the pre-giow timer functioning correctly?

has three

I

2L engines has a light gray connector arxJ a silver label: the 5.7L controller has a black connector and a gold latiel These two controllers are NOT interchangeable They have different resistance

"i*

controller

as long as Ute

Does the system have the

the pre-glow timer functioning correctly?

Does the system have the right controller? Is the engine timing advanced These questions must be answered satisfactorily before tackling the accompanying diagnostic procedures. The glow-plug

oft

the pre glow timer isn

glow plugs, replace tfte controller Caution: Prolonged operation of the glow piugs with the arcuit breaker will result in premature failure of the plugs

there are a few other things to look at before you get into the

troubleshooting procedures:

Current at plugs only

If

breaker

cult

nents.

4

Is

IS off

CYCLE ONCE

trations).

3

and 6.5L V8 engines

for

.

plug)

I

No

Current

I

-

If OK, go to chart 'THERMAL CONTROLLER CHECK"

CHECK

AMP FUSE

20

•

Fuse Blown I

Fuse

Disconnect glow plug relay connector at relay Install new 20

OK

amp

fuse and (urn ignition to run I

Listen for glow plug relay operation Should be clicking on and off If engine is cold

.

Fuse Blows

Fuse

OK

I

Locate and repair short

Relay Not Operating

one

Relay Operating

t

Go To Chart RELAY NOT OPERATING"

relay terminal with 2 fusible links. Test light should turn on and off as controller operates relay

Test Light Does

Not

Test Light

Idle

temp

switch, fuel heater, or solenoid circuits 2 L.D. only, throttle switch

Connect l2-volt lest light to ground Touch the glow plug

Reconnecl glow plug relay connector

circuit in

of the following:

Cold Adv/fast

circuits

EPR. EGR. and

TCC

t

Fuse Blows

On Steady

Test Light Turns On and Off

Come On

Locate and repair short in wire from relay to connector and replace diode at glow plug relay (No diode In 1982) (II the diode is shorted or Installed backwards the circuit breaker heater In the controller may be damaged)

Relay contacts shorted Replace

glow plug relay and

Touch

test light to single red wire

all

glow

plugs.

terminal (Batt. feed) on glow plug

Touch each glow plug harness

relay.

terminal with 12'V0lt test light to ground Test light should pulse on/off.

connected

»

Test Light

On

Replace relay (Contacts burned).

.

Test Light Off Locate and repair open circuit In red wire from glow plug relay to battery

2.118a

Fuse

OK

solenoids.

I

Test Light Comes On, All 8 Wire Terminals

Test Light Does Not Come On, One Or More Terminals

\

Disconnect harness from all glow plugs Connect test light to 12volt source and touch each glow plug terminal Light should be on. Replace glow plug If light is off

\ Repair open circuit in glow plug harness If open circuit Is caused by burned wire, glow plug is shorted and should be replaced.

Glow-plug system troubleshooting (1982 through 1984 6.2L engines)

Locate and repair intermittent short In glow plug relay coil feed breaker healer in

circuit (circuit

conlroMer

may b« damaged)

f

GM

Chapter 2

5.7L, 6.2L

2-75

and 6.5L V8 engines

I Chart #2

RELAY NOT OPERATING

I

With

connect 12ground and touch pmk/blk wire m glow plug relay connector ignition in run

volt test light to

Light

On

Light Off

Touch light blue wire terminal glow plug relay connector

Repair open circuit

at

in

pmk/blk

wire from glow plug relay

f

]

Light Off

Light

Replace glow

On

models and 1982-83 models with shutdown switch).

(1984

models without shutdown switch)

1

1982-83

plug relay

Disconnect the glow plug shutdown connector from the glow plug shutdown switch and touch

light

blue wire

in

connector.

f

Light Off

On

Light f

Reconnect the glow plug shutdown connector to the glow plug shutdown switch and with

Repair open circuit in light blue wire from connector to glow plug

engine coolant temperature less than 110°F. touch the light

relay

blue/black wire

f

Light

}

On

Light Off

Disconnect connector at thermal and touch blue wire terminal in connector

Replace glow plug shutdown temperature switch

controller

}

Light

On

Light Off

i

Connect test light source and touch

Repair open circuit in light blue wire from controller to glow plug

to 12-volt

pin 5

and

pin 6

black wires.

}

\

Light

relay.

On Both Wires

Light Off Either/Or

Both Wires t

-THERMAL CONTROLLER CHECK' Go

to

2.118b

Repair open circuit in black wires or bad ground connection to engine.

Glow-plug system troubleshooting, continued (1982 through 1984 6.2L engines)

2-76

GM

Chapter 2

5.7L and 6.2L V8 engines

LOCATION OF TEMPERATURE SWITCH

IN

CIRCUIT

GLOW PLUO RELAY

LT

•03CKT

(NEW)

2.120 Temperature inhibit switch circuit (1984 through 1989 6.2L and 6.5L engines)

Terminal guide for glow plug control switch on 1982 through 1984 6.2L engines

Checking the system circuits

at the

4

connector for the

glow-plug controller 1

at pin

1

(brown

wire).

If

the engine's

off,

there

should be zero resistance in the brown wire to the alternator. Now check the voltage at pin 1 with the engine running. There should be alternator voltage at the pin. Now check the voltage at pin 1 with the engine off. If there's

still

battery voltage present, the alternator

has blown a diode (see

below). Pin 2: There's

plugs.

The blue wire at Pin 3 should have battery voltage when the ignition 3 key is turned on. 4 Pin 4 (orange wire 82MY and dark green wire 83, 84MY) should have continuity with the twin-red-wire terminal on the glow-plug relay. 5 Pin 5 (black wire) should have continuity with Pin 6 (black wire) and with ground. 6

Pin 6

the voltage reading isn't,

is

as specified, the controller

Disconnect the positive lead

5

and connect

it

With the

6

is

working normal-

replace the controller. of the

meter from the power relay

coil

to the relay output.

ignition switch

still

on, the meter should continue to repeat

the on-off cycle described above.

7

If it

does, the correct voltage

is

being applied to the glow plugs.

Checking the thermal controller

no connection to this pin on 1982 vehicles. On 1983 and 1 984 vehicles, there may be a white tube or a wire to this pin, but it's only purpose is to seal the connector in position. It's hooked to the wire harness. DO NOT GROUND THIS PIN FOR ANY REASON, or you will upset the operation of the controller and may even damage the glow 2

If

ly. If it

Check the resistance

PIUO

CONTROLLEB

BLUEfBLACK ST

TEMP SWITCH

2.119

GLOW

506 CKT.

LT.

INHIBIT

WIRE ASSEMBLY

BLUE 1.0MM', 1000MM. LONG

903 CKT. LT BLUE/BLK. 1.0MM', 950 MM.

(39.4-INCHES)

LONG

(37.4.INCHES)

CONNECTOR

CONNECTOR

6294628

2984528

Use with Temperature Switch #15599010 Connector Body #2977253 also required. 2.123

Here's

how the new

Glow-plug temperature

circuit looks with the inhibit switch installed (1982

inhibit

and 1983

C, K,

in

6.2L Diesel Engine.

G and P trucks with

6.2L and 6.5L engine) 12031493

switch (1984 through 1989 models

with 6.2L and 6.5L engines) Diesel engines which are already in

warm climates,

warmed

up,

and engines operated them start. GM

ENGINE WIRING

HARNESS ASSY

don't always require glow-plugs to help

installed a temperature inhibit switch (see illustration) in the glow-plug systems on 1984 through 1989 vehicles with 6.2L engines. The inhibit switch is located in the wire between the glow plug relay and pin 3 of the controller, which is located in the rear of the right (passenger's side) cylinder head, across from the glow-plug controller (see illustration). The switch opens above 125-degrees F and turns off the glow plugs. This reduces needless glow-plug cycling, which gives the glow plugs a longer service life. As a result of improvements in the design of the controller in the latest version of the system, the switch was dropped after 1989.

Installing the

FWD LAMP WRG HARNESS ASSY.

BLUE WIRE

To modify the four-way engine harness connector, of the light blue wire from the engine-harness half of the connector assembly, install the new connector body (part no. 2977253) at this terminal, plug the mating connector of the new jumper wire assembly (light blue wire with black stripe) into the new connector body, insert the female terminal of the jumper wire assembly into the empty cavity of the four-way connector and reconnect the connector (1982 and 1983 C, K, G and P 2.124

remove the female terminal

glow-plug inhibit switch on earlier 6.2L diesels

If you own a 1 982 or 1 983 C, K, G or P truck with a 6.2L diesel engine, you can retrofit an inhibit switch to prolong the service life of the glow

plugs. 1

Disconnect the cables from the negative terminals of the batteries.

2

Drain

some

of the coolant.

Replace the cover on the right rear head (see illustration) with the 1 984 through 1 989 style cover (part no. 1 4028949, the same cover as the one on the left head). Use a new gasket (part no. 14028951). 4 Coat the threads of the new temperature switch (part no. 1 559901 0) with pipe thread sealer, install the switch and tighten it to 13 to 20 ft-lbs. 5 Replace any lost coolant. 6 Referring to the accompanying wiring schematic (see illustration), connect the glow-plug inhibit wire assembly to the switch with the light 3

blue wire (the one without the stripe), the switch terminal.

where the wire terminal mates

with

trucks with 6.2L engines)

Route the wire assembly toward the left side of the vehicle and strap it engine harness as required. 8 Unplug the four-way engine harness connector (see illustration) from its mate on the glow-plug relay extension harness (part no. 12031 7

to the

1493).

1

2-78

Chapter 2

GM

5.7L and 6.2L V8 engines BArrCRY CABLI

BULKHEAD CONNECTOR

Remove the female terminal of ttie light blue wire from the engine har9 ness four-way connector and install connector body (pari no. 2977253) on this terminal. Plug the mating connector on the new jumper wire assembly blue wire with the black stripe) into 2977253. female terminal of the jumper wire assembly into the empty cavity of the four-way connector. Reconnect the four-way connectors. (light

Insert the

1

Reconnect the

1

^

batteries.

BOOSTEn ASM

Curing engine run-on on 1983 G-model trucks with 6.2L engines On 1983 G-model trucks, an electrical feedback signal from the alternator can cause the engine to continue running with the key in the Off posi-

BULKHEAD CONNECTOM

pump solenoid from shutting off the To correct this condition, you'll need to install a jumper wire kit (pan no. 1 2038051 ) as shown (see illustration). (This jumper assembly was installed by the factory in G-trucks manufactured after fvlarch

tion.

This signal prevents the injection

\

N

I

fuel supply.

RADIATOR ASM

^

(BROWN WIRE1

1983).

Detach the cable from the negative battery terminal. Remove the engine harness connector at the firewall. Looking into the terminal end of the bulkhead connector, locate the 3 #25 circuit (brown wire) and remove it. Insert the end of the jumper harness into the bulkhead connector. 4 Using the terminal supplied with the jumper wire kit, connect the other 5 end of the #25 circuit (brown wire) to the jumper harness. 6 Attach the connector to the firewall. Reattach the cable to the negative battery terminal. 7

1

CIRCUIT f2S

1

BROWN WIRE

r

I

2

(later): Electronic glow-plug control system (1985 through 1993 6.2L and 6.5L models)

y

System No. 4

The glow-plug system on 1985 and

later vehicles with

installation details for installation of jumper wire harness on 1983 G-modeltrucks with 6.2L engines

2.125

6.2L engines

consists of an integral electronic controller/glow-plug relay assembly, eight six-volt glow plugs,

a glow-plug

light

and a glow-plug inhibit tempera-

ture switch.

The

electronic controller/glow-plug relay

assembly contains the

cir-

which monitors and controls the operation of the glow-plug relay. Inputs at pins B and C of the controller (see illustration) provide the information it needs to determine the operating requirements of the glow plugs. Pin B senses "engine cranking." Pin C senses glow-plug voltage through the glow-plug inhibit switch, which is wired in series with the glowplug voltage sensor lead to the glow plugs. The electronic controller is mounted on the rear of the left head. The glow-plug inhibit switch opens at about 1 25-degrees F to prevent operation of the glow plugs above this temperature. There must be battery of the controller to prevent an operational amplifier inside voltage at pin from inverting to ground. If this occurs, the transistor that turns on the glow plug relay opens, preventing the glow plug from operating. Here's how the circuit works: When you turn on the ignition key (engine not running and at room temperature), the glow plugs go on for 4 to 6 seconds, then off for about 4.5 seconds; after that, they cycle on for about 1 .5 seconds, then go off for about 4.5 seconds, then on for another 1 .5 seconds, then 4.5 off, etc. for a total duration of about 25 seconds (including the initial 4 to 6 seconds). If you crank the engine during, or after, the above sequence, the glow

cuitry

plugs

will

cycle on and off for a total duration of 25 seconds

ignition switch returns

starts or not.

from

its

AFTER

the

cranking position, whether the engine to be running to terminate glow-

The engine doesn't have

plug cycling.

The cycling times used here are approximations - they vary somewhat in accordance with engine temperature. The initial "on" time and the on and off cycling time also vary, depending on system voltage. Longer "on" times are produced by lower voltage and/or temperature. The duration of the cycling time is lengthened by a lower voltage and/or temperature. The inhibit switch is calibrated to 1 25-degrees F; above this temperature, the switch opens and the glow plugs aren't energized. The "always closed" switch is always on, and the glow plugs will energize unless the engine temperature is above 110-degrees F. If the system doesn't operate as described here: Check all connectors and verify that they're a tight fit. The ground 1 connection for the engine harness is critical on all 6.2L diesels. Make sure the nut is tightened securely and the ground ring terminal is tight.

2 and 3 4

Check the four-wire connector on the latched, the glow plugs

may

controller.

If it

isn't fully

seated

not function.

Check both stud nuts on the controller, f^ake sure they're tight. Check the temperature switch connector at the glow-plug inhibit

switch, or the "always closed" (always on) switch.

If

this

connection

isn't

good, the glow plug won't come on (and engine temperature must be below 110-degrees F for the plugs to operate). 5 If the glow plugs function normally, but the "glow plugs" light doesn't, check the connections in the harness behind the instrument panel and the bulb in the dash. 6 If all connections are intact, but the glow plug system doesn't operate as described, proceed to the general electrical diagnosis chart (see illustration).

Diagnosing the glow-plug system If the glow-plug system still fails to work correctly, follow the troubleshooting procedure outlined in the accompanying diagnostic flow chart (see illustration) to troubleshoot a problem with the glow plug system. Diagnosing a "no after-glow" problem The glow-plug controller provides glow-plug operation cold engine. This after-start operation is

returned to

tion

Run from

is initiated

when

after starting

a

the ignition switch

the Crank position. Loss of the after-start opera-

smoke and/or poor idle quality after To check for proper operation of this circuit: Turn the ignition switch to the Run position and allow the glow plugs to can

result in excessive white

starting. 1

cycle.

Wait two minutes, then turn the ignition switch to Crank for about one (the engine need not actually start) and return to Run. The glow plugs should cycle on at least once. 3 If the glow plugs don't turn on, unplug the controller connector and check the B terminal of the harness connector with a grounded 1 2-volt test light. The light should be off with the ignition switch in the Run position, and 2

second

on with the switch 4

If

in

the Crank position.

the light doesn't operate correctly, repair a short or

open

in

the pur-

ple wire of the engine harness.

5 If the light operates correctly, but the after-glow feature doesn't, place the controller.

re-

—

J

GM

Chapter 2

2-79

5.7L and 6.2L V8 engines

UNFUSED

BATTERY FEED

MATING CONNECTOR IS

2.126a

12066171

GLOW PLUG VOLTAGE

Typical electrical circuit for (later): Electronic

SENSE INPUT

System No. 4

^

ENG. CRANKING INPUT

glow-plug control system (1985 through 1993 6.2L and 6.5L engines)

GLOW PLUG

INHIBIT

TEMP. SWITCH 23500830

GLOW PLUG

INHIBIT

TEMP. SWITCH (OR "ALWAYS CLOSED" SWITCH)

GLOW PLUG FEED

"GLOW PLUGS" LAMP

9G

EOR SOLENOID

TO WATER

(VEHICLES LESS THAN

IN

FUEL SENSOR

8S00QVW)

(6

VOLT^

TO EOR VENT

PCM

SOLENOID (VEHICLES LESS THAN 8500 GVW)

QLOW PLUG

TO

GLOW PLUGS

IGNITION •*

swrrcH JUNCTION

—

20

AMP (U/H)

A_— 539PNK—

BLOCK

B+

-•

•

r*T-

B_

-2RED-

— 505 YEL

£1— 160BLK

GLOW PLUG

2.126b Electrical circuit for the PCM controlled glow plug system (1994 and later models)

RELAY

-GLOW PLUGB

+-^ -GLOW PLUG-

X SSi &

10

AMP 507

GLOW PLUG SIGNAL

DK BLU

LAMP

609 ORN/BLK

System No. 6: 1994 and later PCM controlled glow plug control system On 1 994 and later models, the PCM controls the on-off time of the glow plugs through the glow plug relay.

glow plug system

is fairly

The design of the computer controlled

simple and

some

diagnosis can be performed

using the previous methods described for the

System 4

(later) electronic

system. Refer to the circuit illustration for wire color codes and components used (see illustration). To properly diagnose an unusual problem,

a

SCAN

from the

tool

must be used

to retrieve diagnostic trouble

codes (DTCs)

PCM.

engine block, in the center freeze plug hole in the block. The block heater is designed to plug into a three-prong (grounded) 110-volt A.C. outlet. If you have to use an extension cord between the heater cord and the wall outlet, make sure you use a heavy-duty cord with a grounded three-prong plug; a smaller household-type cord will overheat and could cause a fire. Leave the heater on for at least two hours to warm up an engine with

30W oil when the temperature is between

and 32-degrees F; leave it on hours to warm up engines with 30W, 1 5W-40 or 1 0W-30 oil when the temperature drops below 0-degrees F. After using the block heater, always store the cord properly to keep it away from hot or moving

for at least eight

parts.

Block heater - check and replacement If

the temperature drops below 32-degrees F for engines with

Check

SOW oil,

F for engines with 1 5W-30 or 1 0W-30, the block heater must be used to warm up the block so the engine can turn over fast enough to start. The block heater is located on the left or right side of the

or below 0-degrees

Check the cord for continuity. Unplug both ends and test the wires ohmmeter or continuity tester. There are three separate wires, the center one is a ground and the two outer ones are "live". Look for damage 1

with an

such as opens and shorts, and replace the wire

if

necessary.

,

2-80

GM

Chapter 2

and 6.5L V8 engines

5.7L, 6.2L

6J LITER DIESEL ELECTRICAL SYSTEM DIAGNOSIS

ENGINE CONTINUES TO RUN IGNITION KEY OFF

I

ENGINE CONTINUES TO RUN Disconnect pink wire injection

pump

ENGINE STAYSON FAST IDLE I AT ALL TIMFS I

Turn A/C fait idle

ull. ignitlun 0(1 and diKonr>«ct solenoid - dark gtrtn wire 1

at

f

solenoid

SOLENOID DOES NOT RETRACT

SOLENOID RETRACTS

1

Check

ENGINE STOPS

ENGINE CONTINUES TO RUN

Check

If

replace ignition switch. Check ign $w. assoc.

Remove

wiring.

injection

linkage

is

\fnrt

Ditconrwrt

conr>ector at fait idle

temperature sw

replace solenoid.

*

ENGINE RUNS ROUGH ON COLD START GLOW PLUGS NOT CYCLING ON AND OFF AFTER ENGINE STARTS - 20 AMP FUSE OK

i

for repair.

Check

2

If

OK,

Stop engine

pump

throttle tli^tly

binding

OK.

ignition switch

adjustment.

Connect lolefHMd wire Op»n

throttle linkage

or solenoid plunger for

for loose Bt wire

SOLENOID RETRACTS I

1

Check continuity of temperature switch with powered test li^t

at generator.

self

open circuit in the orn wire from controller to glow plug relav or an op)en heater element between pin 4 and 5 of the controller will cause (All

this

(KD 125or eouiv) continuity below 9(ff no continuity above 122^ Replace switch if txad

condition)

WITH IGN OFF

NO CONTINUITY

—

Using self powered test lite check continuity of om wire from pin 4 of controller, to the glow plug relay

'

Repair open circuit in

orn

wire from controller to

CONTINUITY

relay.

\ Disconnect controller

INCORRECT READING OR OPEN CIRCUIT -

high impedance millimeters check pin 4 to pin 5

Controller

is

defective.

resistance (should be

27

2.127

2

If

the wires are

General electrical troubleshooting chart for 1985 through 1993 6.2L and 6.5L engines

OK, connect an ohmmeter to the two terminals

of the

block heater. There should be a very low resistance reading (near zero).

the

ohmmeter shows

the heating element to be

open

(infinite

ohms),

If

re-

place the block heater

3

If

and plug a work light into it. Then plug the heater into the other The light should dim slightly. If does, current is flowing the block heater Check for heating by feeling near the block heater.

side of the outlet.

it

If

heat

Charging system - general information and precautions The charging system includes the

the previous checks indicate no problems, choose a double electri-

cal outlet

to

n 3;

is

given

4 If the heater

off,

light

the unit

is

is

given

off,

The purpose

replace the block to

Replacement /4//01V

Drain the coolant (see the Maintenence portion of this Chapter).

Connect the power cord. Refill and bleed the cooling system. Test the block heater as described previously.

Run

of the voltage regulator is to limit the alternator's voltage

fusible link

is

a short length

gine compartment wiring harness.

diameter than the circuit

Unplug the electrical connector from the block heater 2 Remove the center screw and pull the block heater out of the engine. 3 4 Clean the sealing surfaces in the engine block and install the block heater Be sure the seal is intact and tighten the center screw securely. 5 6 7 8

internal voltage regu-

the engine and check for coolant leaks.

etc., dur-

peak voltage output.

The the engine to cool completely before following this proce-

dure. 1

an

link

a preset value. This prevents power surges, circuit overloads,

ing

Warning:

a charge indicator, the battery, a fusible

belt at the front of the engine.

working.

doesn't dim and no heat

alternator,

and the wire between all the components. The charging system supplies electrical power for the ignition system, the lights, the radio, etc. The alternator is driven by a drivelator,

tification flags

it

of insulated wire integral with the en-

The

link is four

wire

gauges smaller in and their iden-

protects. Production fusible links

are identified by the flag color

require periodic maintenance. However, the drivebelt, battery and wires and connections should be inspected at the intervals outlined at the beginning of this Chapter The dashboard warning light should come on when the ignition key is turned to Start, then go off immediately. If it remains on, there's a malfunction in the charging system (see the following Section). Some vehicles are also equipped with a voltmeter If the voltmeter indicates abnormally high or low voltage, check the charging system.

The charging system doesn't ordinarily

,

.

Chapter 2

GM

5.7L, 6.2L

2-81

and 6.5L V8 engines

1985 Through 1993 Glow Plug System Diagnosis (C/K, RA/, G, P)

Engine does not

-

"GLOW PLUGS"

lamp may or may not come "ON"

Fuel system checked and is OK. is 12.4 volts or more with IGN "OFF." Cranking speed OK (100 RPM or more). Reference electronic glow plug system Figure 6-33 for wiring harness terminal identification.

1

Battery voltage

2. 3. 4.

Use

start cold

measure voltage

voltmeter to

at battery stud (single red wire)

on glow plug

f

controller.

No Voltage

Battery Voltage With ignition key "OFF" measure voltage at glow plug feed stud (twin lead) on glow plug controller.

Locate and repair battery

to

circuit.

Battery Voltage

all glow plugs. Use ohmmeter between glow plug terminal and engine block (ground). Replace glow plug if measurement is greater than 2 ohms. Reconnect all glow plugs before continuing with diagnosis.

Disconnect harness from

measure

glow plug controller

^

f

No Voltage to

1

continuity

Relay contacts shorted. Replace glow plug controller all glow plugs.

and

~1

Remove controller connector and measure voltage at harness connector terminal "D" with the (1988 with LH6, remove coolant sensor harness connector before measurement.) f

"RUN.

Locate and repair ignition feed circuit to controller. (1988 with LH6, refer to cold advance electrical system check.)

1

continuity

between terminals "C" and "E"

of connector.

f

Less than 2 ohms

Greater than 2

Reconnect controller harness connector and ensure complete engagement (connector locking latch should "click"

in

t

Measure continuity between terminal "E" of connector and engine block (ground). If measurement is greater than 1 ohm, locate and repair ground circuit to

Measure

key

No Voltage

Ignition Voltage

controller.

ignition

over controller locking tab). Measure the voltage

glow plug feed stud (twin lead) on glow plug controller when turning the ignition key from "OFF" to "RUN." at

—

Remove connector

ohms

from temperature

inhibit

switch

used on 1988 with LH6) and measure continuity between the two terminals on the switch. (Open above 125T.) (not

i

y

f

Less than

1

ohm

Greater than

Locate and repair circuit between connector at pin C and glow plugs.

1

ohm

Replace temperature switch and return to terminal "C" to "E" continuity test.

f

No Voltage

Battery Voltage

Measure the voltage

at any one glow plug harness both right and left banks) when turning the ignition key from "OFF" to "RUN."

connector

Replace glow plug

controller.

(test

f

Battery Voltage If instrument panel "GLOW PLUG" lamp does not come "ON." locate and repair bulb or circuit.

2.128

No Voltage Locate and repair glow plug feed

circuit to

Glow-plug system troubleshooting chart for 1985 through 1993 6.2L and 6.5L engines

glow plugs.

)

2-82

Chapter 2

GM

and 6.5L V8 engines

5.7L, 6.2L

(JhtfCk itie fusible link

d)

(il

equipped)

local'

and the alternator s burned. a< the cirouit and replace the link (the engir>e won start arxlor ir>e ai cessones won work the fusible link blows) Sometimes a fusibiilink may look good, but still t>e bad indoutM. remove and chec*lenoid

If ii

i

it

t

If

it

for continuity

engine and check the alternator lor abnormal notses shneking or squealing sound indicates a bad t>eanng)

e)

Start the

f)

Check

the specific gravity of the battery electrolyte

charge the battery (doesn

Make sure the battery

g)

is fully

cause overcharging by the

It

it's

tow

apply to maintenance tree batteries

t

-$ LT GRN 384ISXLI

CO I

Q—

12004885

8

a,S^—

g

BUS BAR GRD

BLK 150A— BlK 150B

ASM

'^°' 0503

FUSE BLOCK

4

t

WO

SHIFT

LEVER LIGHT

OPENS MOMENTARILY ON 4 3 ON SHIFT

CLOSES WITH CLUTCH

1200426?-.^

A-j/-

GRY8-

8

-r-c^ 4 TH

UM"

12004715

ACC FUSED 15

RELAY

TESI

BRAKE SWITCH 8

WO

4

1201099;

z

^-.CONTACTS

i

fflONT Of

-

REf

HSIOP LAMP2

y83j--f

\.

FLOOR UNDER'

23 5

ENGAGED

WD

OR NEUT tafflB(^ 2

CC SOL

OHMS

8

BLK I50B-

8

WHT

156A-

12015792

RPO MD8 TRANSMISSION

ASM

TRANSFER CASE

2.178

ENGINE SPEED Idle to 15°

Typical electrical schematic for TCC-switch on a

EGR Open

15Mo20°

Open

Full

Vacuum

Closed

Energized (Vacuum

Open

Not Energized (No

to Valve)

Vacuum

to Valve)

Open

Energized (No

Closed

Throttle

EPR SOL

to Valve)

Not Energized

(Vacuum

Throttle

20° to

Not Energized

(Vacuum

Throttle

EPR VALVE

EGR SOL

VALVE

K truck equipped

to Valve)

Not Energized (No

Vacuum

to Valve)

to Valve)

with an

MD8 700-R4

automatic transmission

4 Remove the vacuum hose from the EGR valve. The valve head should drop and the exhaust noise should diminish significantly. Reattach the hose. At idle, the hose to the EGR valve should have about 20 inches of 5 vacuum. If vacuum isn't present, check the output of the vacuum pump at the pump. It should produce at least 20 in-Hg. If vacuum is present at the EGR valve, but the valve doesn't open and 6 is attached and detached, the EGR valve is stuck. Try to you can't get it working, replace it (see illustrations). 7 Manually operate the throttle lever at the injection pump through 1 5 to 20-degrees of travel. The EGR valve should close when the TPS reaches

close as the hose "unstick"

it;

if

the calibrated point.

8 2.1 79

EGR

operation (1 982 through models with 6.2L engine)

1

987

Verify that battery voltage

the ignition switch

is

is

turned on.

any loose connections, an open

present If

in

the pink wire to the

battery voltage

isn't

the wire or a blown

in

TPS when

present, check for

20-amp gauge

idle

fuse.

Check the wiring connections and make sure nothing's loose. Check it's blown. Turn the key on and make sure there's and replace battery voltage in the blue wire from the TPS. This blue wire feeds the EPR 9

indicator switch in the transfer case.

When

If s

grounded

in

either "4 high" or "4

the fuse

it if

grounded, the normally closed relay is switched to open, interrupting the battery voltage path to pin B of the connector at the transmission. The only way to get the converter to operate in 4WD is

solenoid. At

idle,

if

doesn't, the

TPS

is

to close the fourth-gear switch in the transmission, allowing battery volt-

10

parallel path at pin A to pass through the contacts of the fourth gear switch to the TOG solenoid.

throttle

low."

the relay

is

age from the other

now

closed

With the engine

1

EGR

in

it.

ignition switch turned on,

EPR

battery voltage to the

TPS

is

operate the

about 15-degrees, the TPS will (blue wire); at about 20-degrees, the

travel. At

EGR

(yellow wire).

bad. Replace

If it

doesn't oper-

it.

Verify that the electrical connections are

good

at the

EGR/EPR sole-

noid assembly and that the hoses are routed correctly and connected to the solenoids.

EGR valve should be open (the valve head its "up" position and there's exhaust noise at the intake). the EGR

With the engine at idle, the

If

open, check and correct any electrical and hose connections which may be loose and/or disconnected. isn't

cut

ate as described, the

valve (see illustration).

valve

and the

cut out battery voltage to the

Diagnosing the EGR/EPR system on 6.2L LH6 engines Start the engine and warm it up until the thermostat opens. 1 Remove the air cleaner so you can observe the operation of the 2

is in

off,

through 20-degrees of

TPS will

3

the pink wire has battery voltage, but the blue one

bad. Replace

12

If

there's

vacuum present at the solenoid assembly and the solenoids

are receiving an electrical signal as described above, but the

operate the

Replace

it.

TPS doesn't

EGR and/or EPR valves, the solenoid assembly itself is faulty.

Chapter 2

GM

2-107

5.7L and 6.2L V8 engines WASTEGATE

EGR VALVE

UPPER INTAKE MANIFOLD

SOLENOID

FRTl^

CLEANER HOSE

AIR

INLET MANIFOLD (ENGINE)

EGR VALVE LH6 ENGINE (LT.

DUTY)

TURBOCHARGER WASTEGATE

2.180a To replace the EGR valve on a 6.2L and early 6.5L engine, remove the air cleaner, detach the air cleaner hose and unbolt the valve - installation is the reverse of removal

2.1 81 a

2.180b 6.5L Turbo-diesel

Typical gage blocks for

2.181b

Adjustment tool (Kent-Moore J-33043) for the on 6.2L and 6.5L engines

EGR

valve location

TPS adjustment tool

Throttle Position Switch (TPS)

3

bad diode in the solenoid assembly (EGR system on 1982 6.2L LH6 engine) Identifying a

On 1982 LH6

engines, a condition exists that can allow excessive electrical feedbacl< to short out a diode in the EGR and/or EPR solenoids.

The diodes are

for radio noise

usually blows the

20

suppression only.

amp gauge fuse.

When the diode shorts,

the fuse blows, there won't be any power to electrical components such as the glow plugs, cold advance, it

If

AND the EGR system won't operate either. When the EGR system malfunctions, full vacuum is supplied to the EGR valve at all speeds, resulting in heavy black exhaust smoke and low power. To prevent the diodes from shorting out as a result of heavy feedback loads, a special jumper hamess with a built-in diode to reduce feedback load (part no. 14048052) is available. If you've noticed heavy black exhaust smoke and traced the condition to a diode in the EGR/EPR solenoid

fast idle, etc.

assembly, here's

how

to install the

jumper:

Stop the engine and turn the key to the Off position. 2 Disconnect the vacuum and electrical connections to the solenoid assembly.

Remove the solenoid assembly mounting

bolt

and remove the

sole-

noid assembly. Install the new solenoid assembly. 5 Reattach the vacuum and electrical connections to the new solenoid assembly. 6 Disconnect the wire to the TPS and install the new jumper hamess between the connectors. Make sure the blue, pink and yellow wires line up, i.e. are at matching terminals of the connector.

4

7

Install

a new 20-amp gauge

Adjusting the

TPS

The TPS must be adjusted on the throttle shaft of the injection pump. It's not necessary to remove the pump. You'll need a special go-no go gauge and the correct throttle position switch gage block (see illustraDifferent blocks are needed for different applications. tions) to adjust it.

You'll find the correct

1

EGR/EPR

idle fuse.

block for your particular application specified on the

Vehicle Emission Control Information (VECI) label in the engine compartment. Gage block dimensions weren't listed on the VECI label until the 1

983 model

year.

If

the

gage block dimension

isn't specified,

or the

VECI

2-108

Chapter 2

GM

5.7L, 6.2L

and 6.5L V8 engines

GAGE BAR

THROTTLE POSITION

SWITCH CLOSED

SWITCH

OPEN

GAGE TOOL NUMBER

USAGE

ALTITUDE

TRANS.

MODELS

Nationwide

All

Manual

All

14050405

0.646-

0.668'

J-33043-2

Federal

All

Auto.

All

14033943

0.646'

0.668'

J-33043-2

Calif.

All

Auto.

C/K

14033943

0.646'

0.668'

J-33047-2

Calif.

All

Auto.

C/K

14050408

0.602"

0.624"

J-33043-4

2.182

TPS

SWITCH

chart (1982

ENGINE

BROADCAST

THROTTLE

ASM PART#

B/C

POSITION

P/N

LH6 engines

GAGE BAR SWITCH CLOSED

SWITCH

OPEN

GAGE TOOL NUMBER

14050405

.646

.668

J33043-2

14050405

.646

.668

J33043-2

14050405

.602

.624

J33043-4

14050405

.646

.668

J33043-2

14066239

.646

.668

J33043-2

14061550

CODE UHB UHC UHD UHF UHH

14061552

UHJ

14066238

.602

.624

J33043-4

14061560

UHN UNA UHS

14066239

.646

.668

J33043-2

14050405

.646

.668

J33043-2

14050405

.646

.668

J33043-2

14050405

.602

.624

J33043-4

14050405

.646

.668

J33043-2

14066239

.646

.668

J33043-2

14066238

.602

.624

J33043-4

14066239

.646

.668

J33043-2

14061529 14061531

14061545 14061549

14050581

14061573

14061578

UHZ UHR UHT UHU

14061580

UHW

14066299 14061571

14061576

SWITCH

2.183

P/N

TPS

chart (1983

ENGINE ASSEMBLY

THROTTLE

BROADCAST CODES

SWITCH

POSITION

HHB. DHB. FHB HHF. DHF. FHF HMD, DHD, FHD HHJ. DHJ, FHJ HHK. DHK. FHK HHN. DHN, FHN

P/N

HHW. DHW. FHW HHY. DHY. FHY

14050405 14050405 14066239 14066239 14050405 14050405 14066239 14066239

——

23500164

HHR,

,

2.184

TPS

LH6 engines)

GAGE BAR SWITCH

SWITCH

CLOSED

OPEN

.602

.624

.602

.624

.646

.668

.646

.668

.602

.624

.602

.624

.646

.668

.646

.668

.624

.646

chart (1984 through 1986

LH6 engines)

GAGE TOOL NUMBER J33043-4 J33043-4 J33043-2 J33043-2 J33043-4 J33043-4 J33043-2 J33043-2 J33043-4 J33043-2

1

1

1

1

Chapter 2

GM

5.7L, 6.2L

2-109

and 6.5L V8 engines

QAQE BAR

THROTTLE POSITION SWITCH

SWITCH

PART NUMBER

SWITCH CLOSED

OPEN

GAGE TOOL#

14066207

.751

.773

J33043-5

.INJECTION PUMP

EPR BLUE OR VIOLET WIRE

QAQE

Chapter 2

WAVE

ROCKER ARM

WASHER

& BUSHING

GM

5.7L, 6.2L

SPACER

2-121

and 6.5L V8 engines

ROCKER ARM & BUSHING

WAVE WASHER

/

cLEAT & SPACER

/

90°

GAP

WASHER

^

COTTER PIN

W*~~

1983-1984

1982-

2.207

I

An exploded view

of the rocker

arm assembly on the 1982 through 1984 6.2L

diesel engine

ROCKER ARM RETAINERS

REMOVING NYLON RETAINERS An exploded view

2.208

of the rocker

arm assembly on the 1985 and

later 6.2L

and 6.5L diesel engines

will

Fro/^/T

2.209

Instead of loosening each bolt completely, alternate the

bolt pattern to allow the

assembly

to

remain

level

as

it

is

loosened

2.210

A

—

perforated cardboard box can be used to store the to ensure that they are reinstalled in their original locations

pushrods

3 5 6 7

2-122

Chapter 2

GM

5.7L, 6.2L

and 6.5L V8 engines

PIVOT

BRIDGE 2.211

Replace the old rocker arm bridge with this updated version to avoid backfiring or excess noise from the rocker arm assemblies 2.213

The ends of the pushrods and the valve stems should be lubricated with moly-base grease prior to installation of the rocker arms

PIVOT

BRIDGE 2.212 On 5.7L GM diesels, check the rocker arm casting number on the bridge to distinguish the original

air hose adapter is a combination of a special pipe and an air hose fitting - both were purchased at a hardware store

This

2.214

fitting

from the replacement part

Valve springs, retainers in vehicle Apply moly-base grease to the ends of the valve stems and the upper of the pushrods before installing the rocker arms (see illustration). Note: 1978 through 1983 5. 7L engines may experience a valve train ticking noise and/or backfiring condition. This condition may be caused by 1

ends

rocker arm pivot wear. The original rocker bridge (see illustration) must be replaced with an updated version (see illustration) that is distinguished by the casting marks on the bridge. 1 1 Before installing the bolts through the shafts on 1 982 models, be cer-

around the shaft is installed with the split at the bottom (see On 1983 and later, the split is 90-degrees to the right. On 1 985 and later, there is NO split used. On 1 985 and later 6.2L and 6.5L diesel engines, install a new nylon rocker arm retainer (Part #2350076) in each 1/4-inch hole using a drift of approximately 1/2-inch in diameter.

Note: Broken valve springs and defective valve stem seals can be replaced without removing the cylinder head. Two special tools and a compressed air source are normally required to perform this operation, so read through this Section carefully and rent or buy the tools before beginning the job. If compressed air is not available, a length of nylon rope can be used to keep the valves from falling into the cylinder during this procedure. 1

Remove the

ponent.

in

place.

Adjustment 1 Bring the number one piston to top dead center (IDC) on the compression stroke (seethe Timing chain and sprockets -inspection, removal

and installation procedure 14

later in this

Rotate the engine 30-degrees

Chapter).

BTDC

or 3-1/2 inches counterclockwise measured on the balancer. This will position the engine so that NO valves will be close to the piston heads. 1

er 1

Tighten the bolts evenly. Make several passes to insure that the rockarm assembly does not bind at any point. Tighten each bolt to the torque listed in this Chapter's Specifications.

the valve covers. Start the engine, listen for unusual valve train noises and check for oil leaks at the valve cover joints. 1

Install

If

all

of the

Remove the glow plug from the cylinder which has the defective com-

2

illustration 2.207).

Set the rocker arms

valve cover from the affected cylinder head.

valve stem seals are being replaced, remove both valve covers.

tain the ring

12

and seals - replacement

If

all

of the valve

stem seals are being replaced,

all

of the

glow

plugs should be removed.

3

Turn the crankshaft

until

the piston

in

the affected cylinder

is

at top

dead center (TDC) on the compression stroke (refer to the Timing chain removal and installation procedure later in this Chapter). If you are replacing all of the valve stem seals, begin with cylinder number one and work on the valves for one cylinder at a time. Move from cylinder-to-cylinder, following the firing order sequence: 1 -8-4-3-6-5-7-2 on 5. 7L; 1-8-7-2-6-5-4-3 on 6.2L and 6.5L engines. 4 Thread an adapter into the glow plug hole (see illustration) and conMost auto parts stores nect an air hose from a compressed air source to can supply an air hose adapter. Note: hJlany cylinder compression gauges utilize a screw-in fitting that may work with your air hose quick-disconnect it.

fitting.

5

Remove

the rocker arm(s) (or rocker

valve with the defective part and

stem seals are being replaced, be removed.

all

pull

arm

shaft assembly) for the

out the pushrod.

of the rocker

If

all

of the valve

arms and pushrods should

3

8 9

Chapter 2

air holding the intake and exhaust valve closed, compress the springs with a valve spring compressor

Apply compressed

air to

place by the air pressure. leaks

may prevent the air

the cylinder.

2-123

5.7L and 6.2L V8 engines

2.216 Apply a small dab of grease to each keeper as shown here before installation - it'll hold them in place on the valve stem as the spring is released

With the compressed

2.215

6

GM

The valves should be held

in

poor condition, pressure from retaining the valves - refer to the If

the valve faces or seats are

in

procedure below. you do not have access to compressed air, an alternative method can be used. Position the piston at a point 45-degrees before TDC on the compression stroke, then feed a long piece of nylon rope through the glow plug hole until it fills the combustion chamber. Be sure to leave the end of the rope hanging out of the engine so it can be removed easily. Use a large breaker bar and socket to rotate the crankshaft in the normal direction of rotation until slight resistance is felt as the piston comes up against the rope in the combustion chamber. Stuff shop rags into the cylinder head holes above and below the 8 valves to prevent parts and tools from falling into the engine, then use a valve spring compressor to compress the spring/damper assembly (see illustration). Remove the keepers with a pair of small needle-nose pliers or a magnet. Note: A couple of different types of tools are available for compressing the valve springs with the head in place. One type (shown here) grips the lower spring coils and presses on the retainer as the knob alternative

7

If

Remove the bolt (arrow) and bracket and lift the pump from the block (intake manifold removed for clarity)

2.217

turned, while the other type utilizes the rocker arm shaft for leverage. Both types work very well, although the lever type is usually less expen-

is

sive.

Remove the spring retainer or rotator, oil shield and valve spring assembly, then remove the valve stem seal. Several different sizes of valve stem oil seals are used on these engines, depending on intake or exhaust 9

Chapter 4, Valves - servicing. Note: If air pressure fails to hold the valve in the closed position during this operation, the valve face or seat is probably damaged. If so, the cylinder head will have to be removed for additional repair operations. 1 Wrap a rubber band or tape around the top of the valve stem so the valve will not fall into the combustion chamber, then release the air pressure. Note: If a rope was used instead of air pressure, turn the crankshaft slightly in the direction opposite normal rotation. 11 Inspect the valve stem for damage. Rotate the valve in the guide and check the end for eccentric movement, which would indicate that the

valves and oversize valves. Consult the chart

valve

12

is

bent.

Move

bind.

If

aged.

in

the valve

up-and-down

in

the guide

the valve stem binds, either the valve

In either

case, the head

1

Inspect the rocker

14

Reapply

arms

is

and make sure

it

bent or the guide

is

dam-

pressure to the cylinder to retain the valve in the closed position, then remove the tape or rubber band from the valve stem. If a rope was used instead of air pressure, rotate the crankshaft in the normal 15

Lubricate the valve stem with engine

used on the engine.

compress the spring 16

Install

valve.

1

If

oil

felt.

and

install

a new

oil

first,

dab of grease

place if necessary (see illustrathe pressure from the spring tool and make sure the keepit

in

ers are seated.

Disconnect the air hose and remove the adapter from the glow plug If a rope was used in place of air pressure, turn the crankshaft in the direction opposite normal rotation and pull it out of the cylinder. 20 Install the rocker arms and pushrods. 21 Install the glow plugs. 1

hole.

22 Install the valve covers. 23 Start and run the engine, then check for oil leaks and unusual sounds coming from the valve cover area.

Camshaft driven vacuum pump - removal

and installation Do not operate the engine without the vacuum pump in place or pump will not operate, leading to serious engine damage.

Caution: the

oil

Note: Further information on the vacuum pump, including testing procedures, are in the Emissions control Section of this Chapter

Removal 1

in

Remove

each keeper to hold

seal of

the engine has 0-ring type seals,

then install the seal. the spring/damper assembly and shield

Position the keepers in the upper groove. Apply a small

tion).

have to be removed for repair. wear (see the previous Sub-section).

direction of rotation until slight resistance is

the valve spring retainer or rotator and compress the valve

to the inside of

will

for

Install

doesn't

air

the type originally

17

spring assembly.

position over the

2

Remove Remove

the hose from the outlet on the

vacuum pump. pump to

the bolt and the bracket that retain the

manifold (see illustration).

the intake

2-124

Chapter 2

GM

5.7L and 6.2L V8 engines

DRAIN TUBE CLAMP

INTAKE MANIFOLD DRAIN TUBE

SEALER

O RING

Location of the intake manifold drain tube

2.219

Screws should be tightened evenly and to a torque ol 12 N-m Lbs

(9 Ft

)

Clamp assembly m vise m area shown Care should be taken not to

Over tighten

ge-3r

should be

free to turn

when

2.220

installing 'he

screws to the assembly

2.218

pump

Vacuum pump assembly details

Intake manifold - removal and installation The

Lift the pump out of the manifold. The 3 necessary; be sure to replace the 0-ring (see illustration).

pump can be disassembled, if if you disassemble the pump

Exploded view of the intake manifold on the 6.2L and 6.5L GM diesel engines

intake manifold

assembly bolted

to

it.

on the 5.7L engine has a separate

For information on removing and

drain diesel fuel that accumulates

pump into the engine. Make sure the driven gear on the pump meshes with the gear on the camshaft while inserting the oil pump intermediate shaft into the bottom of the vacuum pump. Sometimes making the connection takes some patience and a slight turn until the pump drops down and "clicks" into position. Rotate the pump until the bracket and the bolt can be installed into the 5 Insert the

shaft of the

intake manifold.

6

Install

the

2

Remove Remove

in

the area (see illustration).

The intake manifold on the 6.2L and 6.5L is a combination of an intake manifold and an air

air

crossover assembly (see illustration). It is the spider is completely separated from the coolant system.

plenum type which

This allows the intake manifold to be removed without draining the cooling system. One important detail to remember is that the intake manifold can

be ing

backwards and still operate the engine. However, the mountboss for the secondary fuel filter would be in the wrong position for filter

installed

installation.

vacuum hose.

Belt driven 1

crossover

sembly, refer to the Fuel system Section of this Chapter. The manifold on 1 980 through 1 984 models has a manifold drain tube which is used to

Installation

4

air

installing this as-

vacuum pump - removal and installation

the drive belt. the hose from the

Removal 1

Disconnect the negative cable from the battery. Drain the cooling sys-

tem (5.7L engines

vacuum

pipe.

Leave

it

attached to the

2

only).

•S''3ri

Remove the air cleaner assembly. On 6.2L and 6.5L engines, remove

pump. Remove the mounting bolts. 3 If required, a special puller (available at auto parts stores) must be 4 used to remove the pulley. Do not attempt to remove the pulley any other way. Use a pulley installer to install the pulley.

the crankcase ventilation lines from the intake manifold (see illustration). On 5.7L engines only disconnect the upper radiator hose and the 3

5

shop rags

Installation is the reverse of

removal.

thermostat bypass hose from the water outlet. Also, disconnect the heater hose and the vacuum hose from the water control valve. 4 On 5.7L engines only, remove the air crossover assembly and stuff into the

openings to prevent any objects from

••fiiii

falling inside.

6 7

1

Chapter 2

GM

Remove the clamps from

the crankcase ventilation and remove them from the intake manifold

2.221

2-125

5.7L and 6.2L V8 engines

lines

Remove

2.222

the secondary fuel

filter

from the intake manifold

Label and then disconnect any fuel lines, wires and vacuum hoses 5 from the vehicle to the intake manifold. On 6.2L and 6.5L engines, disconnect the secondary fuel filter adapter (see illustration) and remove the filter as one unit. Detach the throttle rod or cable from the fuel injection pump. If the engine is equipped with cruise control, remove the servo and accessories.

adapter and 6

7 8

Remove the alternator and brackets, necessary. On 5.7L engines only, disconnect the fuel line from the fuel pump and if

the fuel

filter

and remove the

fuel filter with the bracket.

On 5.7L engines only, disconnect the fuel lines at the nozzles using a back-up wrench to prevent twisting the lines. Remove the injection pump 9

and

lines.

not to

(See the Fuel system Section

bend the

injection

pump

lines.

in this

chapter).

Remove

Be very

careful

the fuel injection

pump

mounting adapter and intake manifold drain tube. 10 Loosen the intake manifold mounting bolts in 1/4-turn increments until they can be removed by hand. Follow the opposite sequence as indicated in the installation procedure (see illustration 2.220). The manifold will probably be stuck to the cylinder heads and force may be required to break the gasket seal. A large pry bar can be positioned under the castin lug near the thermostat housing to pry up the front of the manifold. Caution: Do not pry between the block and manifold or the heads and manifold or damage to the gasket sealing surfaces may result and vacuum leaks could develop. Lift the intake manifold from the engine block

2.223

Lift

the intake manifold from the engine block

mm

(see illustration).

Installation Note: The mating surfaces of the cylinder heads, block and manifold must be perfectly clean when the manifold is installed. Gasket removal solvents aerosol cans are available at most auto parts stores and may be helpful when removing old gasket material that is stuck to the heads and manifold. Be sure to follow the directions printed on the container. in

Use a gasket scraper to remove

all traces of sealant and old gasket wipe the mating surfaces with a cloth saturated with lacquer thinner or acetone. If there is old sealant or oil on the mating surfaces when the manifold is installed, oil or vacuum leaks may develop. Cover the lifter valley with shop rags to keep debris out of the engine. Use a vacuum cleaner to remove any gasket material that falls into the intake ports in 1

material, then

2.224a

Intake manifold tightening

sequence on the 5.7L engine

the heads.

12

Use a tap

chase the threads in the bolt holes, remove the debris from the holes. Warning: Wear safety glasses ora face shield to protect your eyes when using compressed air. 13 Apply a thin coat of RTV sealant around the coolant passage holes (5.7L engine only) on the cylinder head side of the new intake manifold gaskets (there is normally one hole at each end). 14 Position the gaskets on the cylinder heads. Make sure all intake port openings, coolant passage holes (5.7L engines only) and bolt holes are aligned correctly and the THIS SIDE UP is visible. 15 Connect the thermostat bypass hose to the water pump. of the correct size to

then use compressed air

.

(if

available) to

the end seals onto the block (5.7L only). Apply a bead of

Install

1

sealant to the edges to insure against

oil

leaks

in

RTV

the corners of the intake

manifold. Carefully set the manifold

1

not

move

in

place.

Do not disturb the gaskets and do

the manifold fore-and-aft after

it

contacts the front and rear

seals.

18 then

Dip each manifold bolt into regular engine install

the bolts. Tighten the bolts to 15

(see illustrations). Work up to the three steps.

final

oil

up

ft-lbs in

to the bolt threads,

the sequence

shown

torque (see the Specifications)

in

2-

GM

Chapter 2

126

5.7L, 6.2L

and 6.5L V8 engines

2.225 Use

penetrating lubricant to soak the threads removing the nuts (arrows) from the studs

4FRT Removal

u,

1

2 3

2.224b

Intake manifold tightening

sequence on the

Disconnect the negative cable from the battery. Remove the air cleaner assembly. Remove the alternator and power steenng braces

On 5.7L engines only, install the fuel injection pump mounting adapter and seal. Note: A special seal installation tool may be needed to install the seal. Install the intake manifold drain tube,

shown (see Install

applying

RTV

sealant as

illustration).

the injection

pump as

(5.7L engines only). Follow the

described in the Fuel System Section sequence and use the proper alignment

marks. 21

The remaining

22

Start the

installation steps are the reverse of removal. engine and check carefully for oil, vacuum and coolant leaks

at the intake manifold joints.

Exhaust manifolds - removal and

installation

Warning: Allow the engine to cool completely before following this proce-

5 6 7

earlier in this Chapter).

Unbolt the dipstick tube.

Remove the heat shields, if equipped. Set the parking brake and block the rear wheels. Raise the front of the vehicle and support it securely on jackstands. Disconnect the exhaust crossover pipe from the manifold outlet (see illustration) Note: Often a oil is necessary to remove frozen exhaust pipe attaching nuts. Use caution not to apply excessive force to frozen nuts, which could shear off the exhaust manifold studs Remove the two front and two rear manifold mounting bolts first, then 8 the center bolt(s) (see illustration) to separate the manifold from the head. Some models use locking tabs under the manifold bolts to keep the bolts from vibrating loose. On these models the tabs will have to be straightened before the bolts can be removed.

short period of soaking with penetrating

dure.

^

WASHER

FRONT OF CAR

BOLT LOCK L.H.

EXHAUST MANIFOLD

(C SERIES)

BOLT LOCK ^puEL

PUMP

WASHER L.H.

EXHAUST MANIFOLD

(E,

equipped) from

Disconnect the glow plug wires and the glow plugs (see the Electncal

system Section 19

(if

the right exhaust manifold.

4

6.2L and 6.5L engine

20

t}efore

K SERIES)

AFTER BOLTS ARE TORQUED TO SPECIFICATIONS, BEND LOCK TABS AROUND BOLT HEADS 2.226 Exhaust manifold installation details on a 5.7L Cadillac engine

GASKET

1

Chapter 2

GM

2-127

5.7L and 6.2L V8 engines

Installation reverse of the removal procedure. Clean and head gasket surfaces of old gasket material, then install new gaskets. Do not use any gasket cement or sealer on exhaust system 9

Installation is basically the

the manifold

gaskets. 1

Install all

the manifold bolts

and tighten them to the torque

listed at the

beginning of the Chapter. Work from the center to the ends and approach the final torque in three steps. 1

Apply anti-seize

compound to the exhaust manifold-to-exhaust pipe new exhaust "doughnut" gasket, equipped.

studs and nuts, and use a

if

Cylinder heads - removal Note: The

5.

and installation

7L diesel engine uses updated cylinder head bolts that must

be replaced when the cylinder head style

head

bolts

may

is

removed and

sen/iced.

The old

stretch without breaking, resulting in insufficient

torque at the bolt. The new style bolt is identified by a dash (-) on the bolt head (see illustration). If the cylinder head is equipped with the newstyle head bolt(s), it is not necessary to replace them. Refer to the chart (see illustration) for the size and location of the updated head bolts. The 6.2L diesel engine uses updated head bolts on 1982 and 1983 models only. The updated head bolts (part number 14077193) are available at a dealership parts department (see illustration).

2.228

On

the 5.7L engine,

each updated head bolt has a part

number and

location in

2.227

30

updated cylinder head bolts

n^^T^

[Vf^ X)

Identification of

(

the cylinder head

X) 30

30


-^^^^t^

ENGINE GLOW

FEEDBACK FROM GLOW PLUGS

GLOW GROUND AFTER CURRENT

PLUG HARNESS

R CYCLING SWITCH HEATER R, AFTER GLOW SWITCH HEATER Rj CIRCUIT BREAKER HEATER R« CIRCUIT BREAKER KEEP ALIVE

CONNECTOR

-1^ X

IGNITION

SWITCH

S,

S, CIRCUIT BREAKER SWITCH S, AFTER GLOW SWITCH

FUSE LINKS 3.75

FUSE

FUEL HEATER

LINK

ENGINE

Control switch electrical schematic

I

TEMPERATURE SWITCH

1983 through 1986 system diagnosis

FUEL

SHUTDOWN SOLENOID WAIT

LAMP

COLD ADVANCE SOLENOID

COLD IDLE FUEL INJECTION SOLENOID PUMP

4' :RY-1-±: BATTERY

POWER RELAY

y^^Twr>—

JlD

RELAY

(T)

~

1983 through 1986 glow plug system electrical schematic

3.76a

liter

engine glow plug

When the ignition switch is turned to the On position, power flows through the ignition switch to pin three of the control switch. The power then flows through resistor R3, switch S2, pin No. 2 (to the latching relay), S3 and pin 6 (to the power relay) (see illustration). While the glow plugs are heating, the resistance heater on switch #1 is also being supplied voltage from the output terminal of the power relay. This starts heating the bi-metal spring on switch #1 and after about ten seconds on a cold engine the bi-metal spring is heated enough to cause switch #1 to open. This breaks the voltage supply to pin #6 and the power relay is deactivated. As soon as there is no voltage feedback from the glow plugs to heat the bi-metal spring on #1 the switch begins to cool and it closes again for a few seconds (with a cold engine). Voltage is again switches S1

supplied by

WAIT LAMP LATCHING RELAY

CHASSIS WIRING

3.74

6.9

,

,

AFTER

GLOW dr ALTERNATOR

HEATER

CYCLING SWITCH

Unplug the glow plug connector

way

of pin

#6

to the input of the

and heat the hot enough.

the glow plugs to heat again

power

relay which

will

resistor for switch #1

,

cause which

would open again when it is This is the cycling process of the glow plugs. The glow plugs help the engine to start quickly, and they continue to operate briefly after the engine starts to reduce white smoke. This cycling would continue indefinitely if it

3.76b

Connect a test light to the glow plug terminal (arrow) - glow plug removed for clarity '

3-39

Ford 6.9L and 7.3L V8 engines

Chapter 3

CONNECT TO ONE LEAD FROM VOLTMETER APPLY

12

VOLTS

TO SIGNAL LEAD

CONNECT ONE LEAD FROM VOLTMETER Using a deep socket, remove the glow plug

3.76c

was

3.77

not for the after-glow signal from the alternator, received after the en-

gine starts. This voltage signal starts heating the bi-metal spring on switch

90 seconds of receiving voltage, the bi-metal spring will have been heated enough to cause switch #3 to open and shut the glow plug system off. Note: If the problem is hard starting, follow the procedures for troubleshooting the glow plug system prior to troubleshooting the fuel

#3. After 20 to

test light

between the glow plug output terminal and ground

After completing a specific repair, repeat the basic diagnostic test to verify that the 1

system

operating properly.

is

Test lamp signal a)

is

correct

Check voltage to each glow plug - Remove leads from glow plugs. Turn

ignition switch to

On

(with the test

lamp

still

connected

to the

Check voltage between each glow plug lead and ground. There should be 1 1 -volts minimum at each lead whenever power

system.

The fast start glow plug system diagnostic procedure describes methods for checking the operation of the glow plug system. Use of these procedures will help in correcting problems. Results of one basic diagnostic test will direct you to one of six specific diagnostic procedures. Basic Diagnostic Test To test the glow plugs, unplug the electrical connector (see illustration) and hook up a test light between a battery positive terminal and the terminal on the glow plug (see illustration). Caution: Whenever disconnecting the glow plug wires from the glow plugs, insulate them from contacting the engine and causing a possible short circuit. If the light comes on, the glow plug is OK. If the light fails to come on, replace the glow plug (see illustration). Tighten the glow plug to the torque listed in this Chap-

Connect a

relay).

lights. If voltage is not detected at any or all leads, check the fusible links, repair vehicle wiring harness or replace the glow plug harness. b) Check glow plug resistance - Turn the ignition switch Off. Using an ohmmeter, measure resistance between glow plug terminal and shell. Replace any glow plug with a reading of 2-ohms or more. Less than 2-ohms is OK. The glow plug system is functioning properly both tests check out correctly. Test lamp on continuously a) Isolate damaged component- Remove all leads from glow plugs before proceeding with this test. With the test lamp still connected to the power relay, turn ignition switch ON. DO NOT START THE ENGINE. Remove harness plug from control switch. If test lamp stays on, remove signal lead (lead from control switch) from power relay. If test lamp goes out, replace the glow plug wiring harness. If the test lamp stays on, replace the power relay. Caution: Do not attach leads to glow plugs until system has been rechecked for cor-

the test lamp

if

2

ter's Specifications.

To diagnose the glow plug system, connect a 12-volt test lamp between the power relay output (to glow plugs) and ground (see illustration). Check test lamp signals as follows:

rect operation.

Engine cold, ignition switch ON, engine not started 1 Test lamp will light when ignition switch is turned ON. Lamp will be for four to ten seconds (depending upon engine 2 lit

b)

ity

cool-

ant temperature).

Test lamp

3

will

ON-OFF

then repeat

cycle. c)

After engine is started 1

Test lamp continues to repeat

ON-OFF cycle

2

Lamp will cycle for a maximum

of

90 seconds

for

20 to 90 seconds. engine is started.

if

switch has fallen below

between

starts.

65-degrees F The system will operate

engine temperature

1

for

a shorter period

of time

than

with a completely cold engine.

Test lamp

2 1

will

remain

off

if

is

at

65-degrees F or higher.

Using the results of the basic diagnostic start of

test,

you can

A

identify

one

of

basic test result

each diagnostic procedure. Pick the procedure Then proceed with the particular tests.

that best fits your basic test results.

I

is

this test.

Check the

If

the lamp

now -

battery state of charge

lights, If

go

to step 5.

the battery

will

crank the en-

operate the glow plug system. c) Replace the fuse in the circuit from ignition switch to control switch - Retest the system. If the system still will not function, but the fuse

the six diagnostic procedures to resolve the problem.

described at the

b)

light

normal and expected with a warm engine (at or above 1 65 degrees F. If the engine is below normal operating temperature, turn the ignition Off. Wait five minutes, then turn the ignition ON again. Observe the monitor lamp. If the lamp still does not light, proThis

gine,

Pinpoint diagnostic test

is

not

ceed with coolant at the control switch probe

With the ignition switch

OK.

is

Lamp does a)

at the

of the fusible links in wiring harness.

OFF, check the continuity between each glow plug connector and power relay output terminal. If any reading is 1-ohm or more, replace the wiring harness. Less than 1 -ohm is OK. Check glow plug resistance - With the ignition switch Off, measure the resistance between the glow plug terminal and shell. Replace any glow plug where resistance is 2-ohms or higher. Less than

2-ohms

after

3

Engine stopped, then restarted 1 Test lamp will light coolant temperature

Check for damage to glow plugs and harness - Check the continu-

it

will

If the system will not function and the replacement fuse blew, remove signal lead from the power relay, replace the fuse, and turn the ignition switch to ON. If the fuse does not blow - replace the power relay. If the fuse blows again,

did not blow, proceed to the next step.

3-40

Chapter 3

Ford 6.9L and 7.3L V8 engines

RIGHT BANK

GLOW PLUGS LEFT BANK

GLOW PLUGS

Control switch connector pin no. 3

3.78

3.79

Chassis connector pin no. 3

RK3HT BANK

GLOW PLUGS LEFT BANK

GLOW PLUGS

Control switch connector pin no. 6

3.80

3.81

Chassis side connector pin no. 6

separate glow plug harness to chassis harness connector. Replace the fuse, turn ignition ON. If the fuse blows, repair vehicle wiring.

d)

e)

If

the fuse does not blow, replace the glow plug wiring harness.

power to power relay - ignition switch Off. Connect a voltmeter between the power relay battery terminal (input) and ground. If less than 1 1 volts is detected, repair the wiring between the battery and power relay. If 1 1 volts or greater is detected, check for power to the control switch (next step). Check power to control switch - With the ignition switch ON and the harness plug removed from the control switch, check the voltage between pin-3 of the control switch connector (see illustration), and ground. If a minimum of 11 -volts is not detected, open glow plug harness-to-chassis connector and test for voltage at pin-3 on chassis side of connector (see illustration). If a reading

Check

of less

battery

than

or greater

1 1

-volts

is still

detected, repair vehicle wiring.

If 1 1

switch connector (see illustration). If less than 1 -ohm resistance is observed, proceed to the next step. If the resistance is 1-ohm or greater, separate the glow plug harto chassis

connector and check for continuity between chassis-side pin six (see illustration) and the power relay trigger lead. If reading is less than 1 -ohm, replace the glow plug wiring harness. If

reading

SIGNAL

OR GROUND

TEST LAMP

is

Check wiring harness continuity - With the harness leads at control switch disconnected, disconnect the power relay signal lead, and check continuity between the signal lead and pin six of the control

ness

INPUT

-volts

detected, replace the glow plug wiring harness. If 11 -volts or greater is detected at the control switch, proceed to the next step. g)

FROM BATTERY

is

greater than

1

-ohm, repair the vehicle wiring.

TO GLOW PLUGS (OUTPUT) 3.82

Checking power relay

for short

Check the power relay for a short - Disconnect all leads except ground to the power relay. Connect a voltmeter between the input and output terminals and apply 1 2-volts to the signal lead input terminal (see illustration). If voltage is detected by voltmeter, replace the power relay. If no voltage is detected, proceed to the next step.

Chapter 3

3-41

Ford 6.9L and 7.3L V8 engines

LEAD FROM OHMMETER

—

SIGNAL APPLY T2 VOLTS

LEAD FROM OHMMETER 3.83

Checking power relay function

3.84

Control switch connector pin no.

AFTERGLOW RELAY HARNESS CONNECTOR

After-glow relay harness connector

3.85

1

CONTROL SWITCH CONNECTOR

After-glow relay harness connector pin no. 4 and control switch connector pin no. 1

3.86

power relay - Disconnect ail leads to the power Connect ohmmeter across input and output terminals of the power relay (see illustration). Apply battery voltage to the signal lead input terminal of the power relay. If there is less than 1-ohm resistance, proceed to the next step. If resistance is 1 -ohm or greater, check ground leak or replace the power relay, m) Check after glow voltage - Remove the harness plug at the control switch and connect all leads to power relay. Turn the ignition switch ON - DO NOT START ENGINE. Check for voltage at the control switch harness plug pin one (see illustration). If no voltage is de-

k)

Check function

of

relay except ground.

I)

tected, replace the

glow plug control switch. If voltage is detected, and replace after glow relay, as

repair alternator or vehicle wiring

necessary.

4

Test lamp continues to cycle beyond the

maximum of 90 seconds fol-

lowing engine start a)

glow voltage - Remove harness plug at the control and check forvoltage at control switch harness Pull harness connector from after-glow relay - Turn the ignition switch Off. Disconnect wiring at the after glow relay and check connector terminal #1 forground (see illustration). If the ground is not OK, repair or replace wiring as required. If the ground is OK, turn the ignition switch to On and check for voltage at terminal #2. 11

Check

after

AFTER GLOW RELAY HARNESS

CONNECTOR

volts is the

After-glow relay harness connector pin no. 4 and chassis connector pin no. 1

3.88

Control switch harness plug sockets no. 4 and 5

minimum acceptable reading.

If the reading is less than as required. If the voltage was a minimum of 1 1 volts, start the engine and check for voltage at terminal #3. The reading should be 6.5 to 7.5-volts. If it is not, repair the wiring or alternator as required. If the harness connector checks out OK, check for resistance between harness connector terminal #4 and control switch terminal

1 1

c)

CONNECTOR

3.87

switch. Start engine b)

CHASSIS WIRING HARNESS

volts, repair the wiring

#1 (see illustration). after-glow relay.

If

If

resistance

resistance

is 1

is

less than

-ohm

1

-ohm, replace the

or greater, disconnect the

chassis-to-engine glow plug harness connector, and check for resistance between terminal #1 of the chassis connector and after-

glow relay connector terminal #4 (see

illustration).

If

resistance

.

3-42

Ford 6.9L and 7.3L V8 engines

Chapter 3

lamp operation

Wait-to-start

Normal operation of wait lamp coolant temperature at control Wail lamp will not come on at all switch probe is at or above 1 65-degrees The wait lamp wil come on when if

the ignition switch If

is in

the start position, for a check of bulb furxrtKXi

coolant temperature

switch

is

Lamp

turned will

is

low the Wait lamp

will light

wtien the ignitton

ON.

remain

lit

4 to 10 seconds depending upon engine cool

for

ant temperature.

Lamp will

then remain

off until ignition

switch

is

turned OFF, then OTj

again.

Check

wait

lamp operation -

operation of wait lamp.

If

refer to the

of normal check glow

above descnption

the wait lamp operation

is

incorrect,

plug system operation using test lamp, as descnbed previously If improper test lamp signal is observed, troubleshoot and repair glow plug system, If glow plug system operation is OK. but wait lamp operation is faulty, proceed to one of the following three tests 1 No wait lamp a) Check lit bulb - If bulb is damaged, replace and recheck wait tamp

as previously described

Latching relay harness connector

3.89

operation. b) is

less than

-ohm, replace the glow plug harness.

1

If it

is 1

-ohm

or

greater, repair the vehicle wiring.

5

Test lamp lights

stays

when

ignition is first

turned on, then goes

off

and

an extended period of time. This is normal and expected with a partially-warmed engine (coolant temperature of 1 40-degrees F or above). If the engine is below 1 40-degrees F turn the ignition OFF. Wait five minutes and turn ignition switch ON again. Observe the test lamp. If the lamp does not light, follow the troubleshooting procedure in Step No. 3. If the lamp

off for

a)

b)

does light, proceed to next step. Check wiring harness resistance - Disconnect harness plug at the control switch, and connectors at power relay and glow plugs. Check resistance between the control switch connector pin four (see illustration), and the power relay output terminal connector. If resistance is 1-ohm or greater, repair harness ground connection,

c)

or replace harness as necessary.

If

resistance

is

less than

1

ohm, proceed to next step. Check wait lamp latching relay resistance - Disconnect the harness connector at latching relay. Check resistance across terminals 1 and 2 of latching relay with red probe (+) on terminal 2 and black probe (-) on terminal 1 If less than 45 ohms, replace latching relay, and recheck system. If 45 ohms or greater, go to next step. Check power relay resistance - Turn the ignition switch Off. Dis-

c)

2

connect the harness plug at control switch only. All other leads must be connected. Check the resistance between control switch connector pin 6 and ground. If the resistance is 2.5 ohms or more, proceed to next step. If the resistance is less than 2.5 ohms, replace power relay. Recheck the system for proper operation. e)

Check

glow voltage -

after

Remove harness plug at the control Do not start engine.

switch. Turn the ignition switch to On. f)

Check

g)

If

h)

The problem should be

i)

If

for voltage at

voltage reading

harness plug pin

is 0,

1

replace the control switch.

Recheck for proper operation. separate the engine glow plug harness-to-chassis harness connector. Turn the ignition switch ON, voltage

is

corrected.

greater than

volts,

do not start engine. Check for voltage on chassis side

of

connector

at pin-1. J)

k) I)

m)

If

no voltage

If

voltage

o) p)

detected, replace glow plug wiring harness.

is still

detected, repair or replace faulty vehicle wiring be-

glow relay and glow plug wiring harness. If voltage is not detected, replace the after glow relay. The problems should be corrected. Recheck for proper operation.

tween n)

is

The problems should be corrected. Recheck for proper operation. If voltage is detected, remove harness plug from after glow relay, and retest.

If

after

voltage

is

detected, repair wiring to alternator or repair the alter-

is

not detected, the problem

nator.

q)

If

voltage

tem

for correct operation.

is

solved.

Recheck the sys-

bulb

is

OK, proceed

to the next step.

- Turn the ignition switch On. Disconnect the harness connector from latching relay Place the jumper wire between harness connector pin 5 and ground If lamp is not lit, repair wiring in circuit from ignition switch to wait lamp to latching relay. If lamp is lit, proceed to next step Check latching relay ground circuit - Turn the ignition switch On. Disconnect the latching relay harness plug. Place the jumper wire at latching relay

between pins 3 and 5 in latching relay hamess connector (see illustration). If wait lamp remains off, repair latching relay ground connection and retest. If wait lamp comes on, replace the latching relay and retest. Wait lamp On with ignition switch On a) Check for grounded lead between wait lamp and latching relay. Turn the ignition switch ON. Disconnect the harness connector at the latching relay. If the lamp remains on, repair ground in the wire between the wait lamp and latching relay and retest. If lamp Is off, proceed to next step. b) Check voltage to latching relay from control switch - Turn the igniOn. Disconnect harness connector at latching relay. With a voltmeter, check voltage between connector pin 2 and ground. If reading is 11 -volts or more, proceed to the next step. If reading is less than 11 volts, turn ignition switch Off. Disconnect

tion switch

.

d)

If

Jump from harness

c)

harness plug at control switch. Check the continuity between latching relay connector plug pin 2 and control switch plug pin 2. If resistance reading is less than 1-ohm, replace the control switch and retest. If resistance is 1 -ohm or higher, repair or replace wiring as necessary. Recheck the system for proper operation. Check continuity to ground at the latching relay hamess socket turn the ignition switch OFF. Disconnect the connector at the latch-

Check resistance between pin-1 and ground. If resis5-ohms or less, replace the latching relay and recheck for proper operation. If resistance is greater then 5 ohms, repair or replace the wiring between the latching relay and power relay. CAUTION: When working on glow plug system, be careful not to short out any components. ing relay.

tance

is

7.3 liter engine glow plug system diagnosis - 1994 earlier (except Direct Injection Turbo) models

and

Glow Plug Continuity Check 1 With the engine and ignition switch OFF, disconnect the wire from a glow plug. Connect a test light to the positive terminal of a battery and to a glow 2 plug terminal (see illustration). 3 If the test light goes ON, the glow plug is OK. If the test light doesn't go ON, replace the glow plug. 4 Repeat this test for each glow plug. 5

Wiring Harness Check 1 With the engine and ignition switch OFF, disconnect the wire from the glow plugs.

3-43

Ford 6.9L and 7.3L V8 engines

Chapter 3

LEAD

CONNECT TO A CONVENIENT POWER SOURCE

TEST

LAMP

GLOW PLUG BULLET TERMINAL

3.90

Glow plug pinpoint test

GROUND WIRE TERMINAL EYELET

TEST TERMINAL 3.91

2

Wiring harness check

3.92

Control unit ground test

Remove the cover from the control module by squeezing the sides to-

gether.

GROUNDED

Using an ohmmeter or continuity tester, check for continuity between 3 each glow plug lead and the test terminal (see illustration) on the control unit. Repair any open circuits as necessary. 4 Reconnect the glow plug wires.

EYELET

Control unit ground test With the engine and ignition switch OFF, connect an ohmmeter to the 1 ground wire terminal eyelet and to the ground terminal on a battery (see illustration).

2

If

the resistance

is

POWER TERMINAL

more than one ohm, clean or repair the ground con-

nection.

3

If

the resistance

is

more than one ohm, perform the supply voltage

test.

A

Supply voltage test 1

With the engine and ignition switch OFF, connect a voltmeter to the power terminal (see Illustration). If there is less than ten volts, repair the wiring or recharge the battery.

CAUTION: DIRECT CONNECTION TO BATTERIES

control unit

2 3

If

there

is

more than ten

volts,

go

to Ignition switch voltage test.

3.93

Supply voltage test

3-44

Ford 6.9L and 7.3L V8 engines

Chapter 3

TEST TERMINAL IGNITION

TERMINAL

3.94

Ignition switch voltage test

Control Unit*

Wait-To-Start

Temperature F

Lamp On Time

3.95

Time

(seconds)

(seconds)

-20 F

7-15

35-70

F

7-12

25-60

35 F

5-12

15-35

70 F

3-5

7-15

105 F

1-3

3-5

140 F

NOT

of Control Unit,

3.96

.^±^

1-3

or less

1

'Temperature

WAIT-TO-START INDICATOR CONNECTOR

Test Light Total

ambient Temperature

Test light chart

3.97

Ignition switch voltage test

Connect the voltmeter to the the control unit and to ground.

ignition terminal

1

2

Turn the

3

If

there

ignition switch

ON,

Wait-to-start indicator test (indicator illuminated)

(see illustration) on

accessories OFF. check the fusible link, recharge the bat-

all

less than eight volts,

is

Control unit functional test

If the Wait-to-Start indicator illuminates, go to the Hard Starting 5 checks.

tery or repair the wiring.

4

If

there

is

more than

eight volts,

go to the Control unit functional test.

Control unit functional test With the engine and ignition switch OFF, connect a test light to the test 1 terminal on the control unit (see illustration).

2

Have an

time the test

Compare the amount of stays on to the Test Light Chart (see illustration). Note:

ON

ON

cycle. If

the test light time

batteries

4

If

is incorrect,

and replace the

the test light time

Wait-to-Start

disconnect the ground cables from the

correct, the control unit

is

OK.

lamp diagnosis

Unplug the Wait-to-Start indicator connector at the control

unit

(see

illustration).

2

Turn

ignition switch

If

the Wait-to-Start indicator stays on, trace

and

repair the wiring to

the Wait-to-Start indicator.

Does Not Illuminate Unplug the Wait-to-Start indicator connector at the control unit. Connect a jumper wire from the harness side to ground (see illustra-

Indicator 1

2

PCM

tion).

Turn the

4

If

ignition switch

On.

the Wait-to-Start indicator stays

repair the wiring.

out.

controlled glow plug system diagnosis - 1994 and

later Direct Injection

Turbo models

Using a voltmeter or 1 2-volt test light, check for battery voltage at the large glow plug relay terminal with the black/orange wire connected to it (see illustration). Battery voltage should be present at all times. If not, check black/orange wire to the starter relay and the fusible links. 2 Turn the ignition key On, the relay should click on and off (when the engine is cold) and battery voltage should be present at the large terminal 1

brown wires when the relay clicks on. remove the valve covers and disconnect the wire connectors at each glow plug. Using an ohmmeter, check for continuity between each glow plug terminal and ground. There should be 0. 1 to 2.0 ohms resistance at each glow plug. Replace any glow plugs with high resistance. Warning: Do not probe the large red-striped wires to the fuel injectors. These wires carry 115-volts DC and can cause a severe If

the relay operates properly,

4

If

the relay does not operate, disconnect the electrical connector at

the base of the relay

off,

replace the bulb or trace and

and check

for battery voltage at the red/light

green

wire terminal, on the wiring harness side of the connector. Battery voltage

should be present with the ignition key On. If not, check the 30-amp glow plug fuse in the fuse box and the wiring from the fuse box to the connector. 6 If battery voltage was present in Step 4, measure the resistance across the two terminals at the glow plug relay. There should be 5 to 15 ohms resistance across the relay coil. Replace the relay if the resistance not as specified. If the relay, glow plugs and related wiring are all good. The problem 7 probably lies within the PCM. Have the PCM check at a dealer service deis

3

or

shock.

On.

If the Wait-to-Start indicator goes off, disconnect the 3 ground cables from the batteries and replace the control unit.

4

Test the glow plugs for continuity and replace as necessary.

3

Indicator stays illuminated 1

more glow plugs are burned

This occurs often

with the

control unit.

is

when two

1

2

assistant turn on the ignition switch.

light

The Wait-to-startAest ligtit may not come on if the engine temperature is at or near normal operating temperature. Total test light time is measured from the beginning of the cycle to the end of the last ON-OFF 3

indicator flashes rapidly

partment.

Chapter 3

Ford 6.9L and 7.3L V8 engines

3-45

GLOW PLUG RELAY

CONTROL MODULE BASE

CONTftOL UNIT SIDE

m=^

MOUNTTING

Glow plug

3.99

Wait-to-start indicator test (indicator not illuminated)

3.98

- 1994 and later Direct Injection Turbo models

relay

/T\ ^

COOLANT HEATER PLUG 3.100b

The block (coolant) heater plug is located low on the side of the engine block

3.100a

move

Block heater - check and replacement

3

The block

"tee" bar retainer.

(coolant) heater

is

located on the right (passenger's) side

engine adjacent to where the

oil

dipstick tube enters the block (see

The block heater wire should be routed forward to the radiain such a way that the wire does not chafe or burn on the exhaust manifold. Be sure the wire is secured at both ends to prevent illustration).

opening

tor grille

it

from being pulled out of place. Block heaters are designed to operate on 120-volts for available

AC power. Check

voltage before troubleshooting the block heater.

heater can be tested is

with the unit

in

in

or out of the engine, however, the easiest

A

block

method

place.

check the cord for continuity. Unplug both ends and test the wires or continuity tester. There are three separate wires the center one is a ground and the two outer ones are "live". Look for damage such as opens and shorts, and replace the wire if necessary. If the wires are OK, connect an ohmmeter to the two terminals of the block heater. There should be a very low ohms reading (near zero) If the ohmmeter shows the heating element to be open (infinite ohms), replace First,

with an

Loosen the center screw (see illustration) and pull the block heater It may be necessary to push it to one side to clear the

out of the engine.

Check of the

Loosen the center screw, pull the heater out, then sideways until the 'Tee" bar clears the opening

it

ohmmeter

.

the block heater.

4

Clean the sealing surfaces

heater.

5 6

7 8

Be sure

the seal

is

Connect the power cord. Refill and bleed the cooling system. Test the block heater as described above. Run the engine and check for coolant leaks.

Fuel heater 1994 and earlier (except Direct Injection Turbo) models General information

An electric fuel heater is incorporated into the top of fuel filter assembly on late models. When ambient temperatures drop below 30-degrees, is designed to warm the fuel as it enters the filter to prevent clogging due to it

low temperature

"jelling".

Test 1

Disconnect the

electrical

choose a double electriand plug a work light into it. Then plug the heater into the other side of the outlet. The light should dim slightly. If it does, current is flowing to the block heater. Check for heating by feeling near the block heater. If

2

If

the test

light

comes

heat

5

If

the test

light

doesn't

6

If

the fusible link

cal outlet

If

is

given

the light

off,

connector at the

fuel

heater (see illustra-

tion).

the previous checks indicate no problems,

If

the engine block and install the block and tighten the center bolt securely.

in

intact

the unit

is

working.

does not dim and no heat is given off, replace the block heater.

wire

3 4

Hold a test light probe to the female socket of the fuel heater harness and connect the test light wire to ground. Turn the ignition switch On and check for power.

is

on, the circuit to the heater

come

burned

on, check the fusible

out,

is

OK.

link.

check the wiring and if the wiring is OK,

replace the heating element.

Replacement Warning: Allow the engine to cool completely before following this procedure. 1

Drain the coolant (see the Maintenance portion of this Chapter).

2

Unplug the power cord from the block heater.

7 If the fusible link is OK, check and repair the wiring. With the temperature below 30-degrees, start the engine and place 8 your hand on the top of the fuel filter housing. If there is voltage at the terminal (as tested above) and the heating element doesn't get warm, replace the element (see illustration 3.9c).

3-46

Chapter 3

Ford 6.9L and 7.3L V8 engines FUEL FILTER

HEADER WITH FUEL HEATER

HEATER RETURN

FUEL FILTER

COOLANT TEMPERATURE SENDING UNIT

ELEMENT

WATER SEPARATOR DRAIN BOWL

VALVE

ENGINE TEMPERATURE

COVER

WARNING LAMP CONNECTOR LOCATION

EXHAUST MANIFOLD

COOLANT DRAIN

The

LUBE OIL

connector is located header (driver's side of F-Series shown, E-Series similar

3.101

on the

electrical

FILTER

fuel filter

OIL DRAIN,

PLUG

1994 and

later direct Injection

Note: The fuel heater

is

controlled

Turbo models The altemator warning light (if equipped) should come on when the ig-

by the Powertrain Control Module

key

turned to Start, then go

immediately.

remains on with

(PCM).

nition

Removal

the engine running, there's a malfunction in the charging system.

Drain the fuel from the fuel filter/water separator. Refer to the cutaway

1

illustration of

the fuel filter/water separator and the previous section on re-

placing the fuel

2 3 4

Remove

5

Remove

is

vehicles are also equipped with a gauge. ly

the cap from the

assembly and withdraw the

filter

element.

If

the

gauge

If it

Some

indicates abnormal-

high or low output, check the charging system.

Be very

filter.

off

when making electrical and note the following:

careful

the alternator

When

circuit

connections to protect

reconnecting wires to the alternator from the batteries, be

Disconnect the wiring from the heating element.

a)

Unscrew the standpipe and remove

sure to note the polarity. b) Before using arc welding equipment on the vehicle, disconnect the wires from the alternator and the battery terminals. c) Never start the engine with a battery charger connected. d) Always disconnect the battery cables before using a battery char-

it

from the housing.

the heater element.

Installation

The remainder of installation is the reverse of removal. Note that the gasket used is bevel cut and must be reinstalled properly to avoid leaks.

6

ger.

Charging system - general information and precautions The charging system includes the

alternator,

an

internal voltage regu-

a charge indicator, the batteries, fusible links and the wire between all the components. The charging system supplies electrical power for the

when the engine

is

running.

The

alternator

is

alternator

serious injury

lator,

vehicle

The

turned by an engine drivebelt which could cause your hands, hair or clothes become entangled in it with the engine running. f) Since the altemator is connected directly to the battery, it could arc or cause a fire if overioaded or shorted out. g) Wrap a plastic bag over the altemator and secure it with rubber e)

driven by a drivebelt

is

if

bands before steam cleaning the engine.

at the front of the engine.

to

The purpose of the voltage regulator is to limit the alternator's voltage a preset value. This prevents power surges, circuit overloads, etc., durpeak voltage output.

ing

1

A fusible link is a short length of insulated wire integral with the engine compartment wiring harness. The cuit

it

link is

smaller

in

diameter than the

cir-

and their identification flags are See the owner's manual for additional informa-

protects. Production fusible links

identified

by the flag

color.

Charging system - check

tion regarding fusible links.

The charging system doesn't ordinarily require periodic maintenance. However, the drivebelt, batteries and wires and connections should be inspected at the factory recommended inter/als.

sume

If

a charging system malfunction occurs, don't immediately asis causing the problem. First check the following

the altemator

items: a)

Check the drivebelt tension and condition. Replace

it if

if s

worn or

deteriorated. b)

Make

c)

Inspect the alternator wiring harness and the connectors at the alternator and voltage regulator. They must be in good condition and tight.

sure the altemator mounting and adjustment bolts are

tight.

5

)

3.103

Remove the adjustment

3.102

bolt (arrow)

Check the fusible link (if equipped) located between the starter solenoid and the alternator. If it's burned, determine the cause, repair the circuit and replace the link (the engine won't start and/or the accessories won't work if the fusible link blows). Sometimes a fusible link may look good, but still be bad. If in doubt, remove it and check Start the engine

and check the alternator for abnormal noises sound may indicate a bad bearing).

(a

shrieking or squealing

Check the

f)

g)

h)

specific gravity of the battery electrolyte.

If

it's

low,

charge the battery (doesn't apply to maintenance free batteries). t^ake sure the battery is fully charged (one bad cell in a battery can cause overcharging by the alternator). Disconnect the battery cables (negative first, then positive). Inspect the battery posts and the cable clamps for corrosion. Clean

them thoroughly

If

if

come

on, reattach the

clamp and

buying an alternator, find out the shop's policy regarding pulleys will perform this service free of charge.

When 7

Installation is the reverse of removal.

8

After the alternator

9

Check the charging voltage

is installed,

check the drivebelt tension.

to verify

proper operation of the alterna-

tor.

system - general information and precautions

Starting The

sole function of the starting system

quickly

enough

The

starting

The

to allow

it

is

to turn over the engine

to start.

system consists of the batteries, the starter motor, the and the wires connecting them. motor/solenoid assembly is installed on the lower part of

to the next step.

the test light

comes on, there is a short (drain) in the electrical The short must be repaired before the

of the vehicle.

If

the light goes out, the alternator

is

If

the ignition key is turned to the Start position, the starter soleactuated through the starter control circuit. The starter solenoid then connects the battery to the starter. The batteries supply the electrical

bad.

the light stays on, pull

will tell

energy to the starter motor, which does the actual work of cranking the en-

The starter motor on a vehicle equipped with a manual transmission can only be operated when the clutch pedal is depressed; the starter on a vehicle equipped with an automatic transmission can only be operated when the shift lever is in Park or Neutral. Always observe the following precautions when working on the starting system: a)

the voltage

is

less, the alternator diodes, stator or rectifier

bad or the voltage regulator

may be

Alternator - removal

and installation

seconds

may be c)

of the batter-

at

a time without pausing to allow it to cool

for at least

1

two

starter is connected directly to the batteries and could arc or cause a fire if mishandled, overloaded or shorted out. Always detach the cable from the negative terminal of the batteries before working on the starting system.

Starter

motor - check

the starter motor doesn't turn at

1

Detach the wires from the alternator. Remove the adjustment bolt (see illustration), then remove the al3 ternator drivebelt (see the Maintenance portion of this Chapter). Remove the lower mounting bolt and separate the alternator from the 4 engine (see illustration).

make sure the

If you're replacing the alternator, take the old one with you when pur5 chasing the replacement. Make sure the new/rebuilt unit looks identical to

and cause

The

ies.

2

it

minutes. b)

malfunctioning.

Detach the ground cables from the negative terminals

Excessive cranking of the starter motor can overheat

serious damage. Never operate the starter motor for more than

approximately 14 to 15 Volts. Turn on the headlights. The voltage should drop, and then come back 4 up, if the charging system is working properly. If the voltage reading is more than specified, replace the voltage reg5 If

is

gine.

each fuse until the light goes out (this you which component is shorted). Using a voltmeter, check the battery voltage with the engine off. It 2 should be approximately 12-volts. Start the engine and check the battery voltage again. It should now be 3 (b)

starter

When

noid

charging system can be checked. 3) Disconnect the alternator wiring harness. (a)

number,

Many new/rebuilt alternators DO NOT have a pulley installed, so you may have to switch the pulley from the old unit to the new/rebuilt one.

necessary. Reconnect the cable to the negative

the test light does not

system

in

6

the engine, next to the transmission bellhousing.

proceed

same

nators.

off, connect a test light between the negative battery post and the disconnected negative cable clamp. If

the

alternator. Finally, look at the

starter solenoid

2)

1

- they should be

on the old

terminal.

1

ulator.

location as the terminals

identification numbers stamped into the housing or printed on a tag attached to the housing. Make sure the numbers are the same on both alter-

With the key

i)

and

bolt (arrow)

some shops

for continuity.

e)

Remove the mounting

the old one. Look at the terminals size

d)

3-47

Ford 6.9L and 7.3L V8 engines

Chapter 3

If

shift lever is in

the clutch pedal

2

Make

tery

and

3

If

is

all

when

the switch

is

operated,

Neutral or Park (automatic transmission) or

depressed (manual transmission).

sure the batteries are charged and

starter solenoid terminals, are clean

all

cables, both at the bat-

and secure.

the starter motor spins but the engine doesn't turn, the overrunning

clutch in the starter motor or replaced.

is

slipping

and the

starter

motor must be

rebuilt

5

1

3-48

3.104

Ford 6.9L and 7.3L V8 engines

Chapter 3

Unplug the

electrical

connector from the

3.105

fuel shut-off

Working from below, disconnect the cablen

'70 thnj '83

dtonMim AHtwic* t b«c«r« 83

thni 87

AUDI

•1666 234 •1

40ooa

«is 428 1117

SOOOall SOOOall

Intrepid

80 ttifu 87 •77t»wu'83

•545

'84avu'88

912

H*al»y Spril*

Dodga/Ply./Chryslar RWD 71 thru 89 Shadow/Plymouth Sundar>ca '87 thm 94

•1779 •349

a Plymouth Acclaim '89 thm '95 Vans - Dodge ft Plymouth '71 thm '96

EAGLE Talon

-

Vision

-

see Mitsubishi Eclipse (2097) see CHRYSLER (25025)

1SS1

Buick Estate

'70 thru '90. Elect7a'70 thru '84.

LeSabre 70 thru '85. Limited Oldsmoblle Custom Cruiser

'74 thru '79 '70 thru '90, Delta 88 70 thru BS.Ninety-eight '70 thm '84 Pontiac Bonneville '70 thru '81. Catalina 70 thm 81 Grandville '70 thru '75, Pansienne '83 thru '86 .

268 2105

AstfX)

&

CMC Safari

•2021

560 334 754

3S9 773

'70 thru '81

thnj '92

Cavalier • see GENERAL MOTORS (766) Celebrity - see GENERAL MOTORS (829) Camaro & Firebird 93 thru 96 Chevelle, Malibu, El Camino '69 thru '87

24017 625 449

Chevette & Pontiac T1000

274

-

Corvette all V8 models '68 thru '82 Corvette all models '84 thm '91 Chevrolet Engine Overhaul Manual Full-size Sedans Caphce, Impala. Biscayne. Bel Air & Wagons '69 thm '90 Lumina - see GENERAL MOTORS (1671) Lumina APV - see GM f2035; Luv Pick-up all 2WD & 4WD '72 thm '82 Monte Cario all models '70 thru '88 Nova all V8 models '69 thru '79 Nova/Geo Prizm front wheel drive '85 thm '92 Pick-ups '67 thru '87 - Chevrolet & GMC. all V8 & in-iine 6 cyl. 2WD & 4WD '67 thm '87; Suburbans, Blazers & Jimmys '67 thru '91 Pick-ups '88 thru '95 - Chevrolet & GMC. all full-size models '88 thm '95; Blazer & Jimmy '92 thm '94; Suburban '92 thru '95; Tahoe & Yukon '95 S-10 a GMC S-15 Pick-ups '82 thru '93 S-10, Gmc S-1S & Jimmy 94 thru '96 Sprint & Geo Metro 85 thm '94 Vans - Chevrolet & GMC. V8 & in-line 6 cylinder models '68 thm '96

1336 1762 704

319 626 241

1642 420 •1664

•831

24071

1727 '345

CHRYSLER 25025 •2058

•1337

•36051 788 •880

649 1670 •1026 •36071

Mazda Pick-ups •1418

1338 •1725

344 •2119

all models '78 thru '82 2402, 260Z & 280Z Coupe '70 thm 280ZX Coupe & 2+2 '79 thm '83

models '78 thru 510 8i PL521 Pick-up 510 all models '78 thru 61 all models '72 thm 31

all

'1671

Grand •766

Buick Skyhawk, Cadillac Cimarron, Chevrolet Cavalier. Oldsmoblle Firenza Pontiac J-2000 & Sunbird 82 thru '94 Buidk Skylark, Chevrolet Citation, Olds Omega, Pontiac Phoenix '80 thm '85 Buick Skylark & Somerset, Olds Achieve, Calais & Pontiac Grand Am 85 thm '95 Cadillac Eldorado ft Oldsmoblle Toronado '71 thm '85, Seville '80 thm '85, Buick Riviera 79 thm '85 Chevrolet Lumina APV, Oldsmoblle

1420

38030 •2035

Silhouette

•2039

& Pontiac Trans Sport '90 thm

'95

•

1

643 346 983 698 697

400 & 600 see CHRYSLER Mid-size -

shown

with

updated

-

models

'90

thm

(1337)

an asterisk

(')

to Include later

HONDA 2067 •42013 160 633 297 1227

1 90 Series 4-cyl gas models, 84 thm '88 230, 250 ft 280 6 cyl sohc '68 thm '72 280 1 23 Series gas models '77 thm '81

450 all models '71 thm '80 Diesel 1 23 Sarias '76 thm '85

350

ft

MGB Roadster GT Coupe '62 thm '80 MG Midget ft Austin Healey Sprite

1 1 1

ft

265

Roadster 58 thm

'80

1

•1669

Cordia, Tredia, Galant, Precis a

Mirage

Eclipse, Eagle Talon

•2022

Pick-up

a

Plymouth Laser '90 thm '94 '83 thm '96, Montero

'83

300ZX all models incl.

thm

thm

'93

NISSAN 1137 •7201 5 •1341 •771

Turtx) '84 '93 thm '97

models models '85 thm '91 thm 96, Pathfinder Pulsar all models 83 thm 86 Sentra all models 82 thm '94 Stanza all models '82 thm '90 Altima

all

Maxima

'89

all

PKk-ups

'80

'87

thm

'95

see GENERAL MOTORS (1420) Custom Cruiser - see BUICK (1551) Cutlass '74 thm '88 Cutlass Ciera

-

see

GM

(829)

Supreme - see

Cutlass

GM (1671)

Delta 88 - see BUICK Full-size RWD (1551) Delta 88 Brougham - see BUICK Full-size:

FWD (1551). RWD (1627)

Delta 88 Royale see BUICK (1551) Firenza see GENERAL MOTORS (766) Ninety-eight Regency - see BUICK -

Full-size

RWD (1551). FWD (1627)

Omega

-

see GENERAL MOTORS (38020) - see GENERAL MOTORS (2035) see GM (38030)

Silhouette

Toronado

PEUGEOT 504

diesel

all

models

'74

thm

'83

PLYMOUTH Laser Other

-

see MITSUBISHI Eclipse (2097) sea DODQE

PLYMOUTH titlet,

T1000 • see CHEVROLET Chevette

-91

«n< -M

a 1900 71 gini-r* 600 a 1900 TWO 4 4 WD to ••U'H

Camry Camry

OH modals -S3 «